U.S. patent application number 10/182432 was filed with the patent office on 2004-01-01 for cyr61 compositions and methods.
Invention is credited to Greenspan, Jeffrey A, Lau, Lester F, Yeung, Cho-Yau.
Application Number | 20040002124 10/182432 |
Document ID | / |
Family ID | 46298836 |
Filed Date | 2004-01-01 |
United States Patent
Application |
20040002124 |
Kind Code |
A1 |
Lau, Lester F ; et
al. |
January 1, 2004 |
Cyr61 compositions and methods
Abstract
Polynucleotides encoding mammalian ECM signaling molecules
affecting the cell adhesion, migration, and proliferation
activities characterizing such complex biological processes as
angiogenesis, chondrogenesis, and oncogenesis, are provided. The
polynucleotide compositions include DNAs and RNAs comprising part,
or all, of an ECM signaling molecule coding sequence, or biological
equivalents. Polypeptide compositions are also provided. The
polypeptide compositions comprise mammalian ECM signaling
molecules, peptide fragments, inhibitory peptides capable of
interacting with receptors for ECM signaling molecules, and
antibody products recognizing Cyr61. Also provided are methods for
producing mammalian ECM signaling molecules. Further provided are
methods for using mammalian ECM signaling molecules to screen for,
and/or modulate, conditions and disorders associated with
angiogenesis, chondrogensis, and oncogenesis; ex vivo methods for
using mammalian ECM signaling molecules to prepare blood products
are also provided. Additionally, modulators, such as peptide
modulators, of an ECM signaling molecule activity are provided.
Further provided are methods for screening for modulators of a
Cyr61 polypeptide-integrin receptor inteaction, as well as methods
of treating conditions and disorders associated with such an
interaction.
Inventors: |
Lau, Lester F; (Chicago,
IL) ; Yeung, Cho-Yau; (Oak Park, IL) ;
Greenspan, Jeffrey A; (Chicago, IL) |
Correspondence
Address: |
Katten Muchin Zavis Rosenman
Patent Administrator
Suite 1600
525 West Monroe Street
Chicago
IL
60661-3693
US
|
Family ID: |
46298836 |
Appl. No.: |
10/182432 |
Filed: |
October 16, 2002 |
PCT Filed: |
January 31, 2001 |
PCT NO: |
PCT/US01/03267 |
Current U.S.
Class: |
435/7.23 ;
424/185.1; 435/320.1; 435/325; 435/69.1; 530/350; 536/23.5 |
Current CPC
Class: |
A01K 2227/105 20130101;
G01N 33/5064 20130101; A01K 2267/035 20130101; A01K 2267/0368
20130101; A01K 67/0275 20130101; G01N 2333/7055 20130101; A01K
2217/05 20130101; A01K 67/0276 20130101; C12N 2830/008 20130101;
G01N 33/5008 20130101; G01N 33/5067 20130101; G01N 33/5029
20130101; C12N 15/8509 20130101; C07K 14/475 20130101; G01N 33/5061
20130101; G01N 33/5055 20130101; G01N 33/5011 20130101; G01N
33/5088 20130101; A01K 2217/075 20130101 |
Class at
Publication: |
435/7.23 ;
435/69.1; 435/320.1; 435/325; 530/350; 536/23.5; 424/185.1 |
International
Class: |
G01N 033/574; C07H
021/04; A61K 039/00; C07K 014/71; C12P 021/02; C12N 005/06 |
Claims
What is claimed is:
1. A method of screening for a modulator of cell adhesion
comprising the steps of: (a) contacting a first fibroblast cell
with a suspected modulator of cell adhesion and a biologically
effective amount of an ECM signaling molecule-related biomaterial
selected from the group consisting of a human Cyr61, a human Cyr61
fragment, a human Cyr61 analog, and a human Cyr61 derivative; (b)
separately contacting a second fibroblast cell with a biologically
effective amount of an ECM signaling molecule-related biomaterial
selected from the group consisting of a human Cyr61, a human Cyr61
fragment, a human Cyr61 analog, and a human Cyr61 derivative,
thereby providing a control; (c) measuring the level of cell
adhesion resulting from step (a) and from step (b); and (d)
comparing the levels of cell adhesion measured in step (c), whereby
a modulator of cell adhesion is identified by its ability to alter
the level of cell adhesion when compared to the control of step
(b).
2. The method according to claim 1 wherein said first and second
fibroblast cells comprise an .alpha..sub.6.beta..sub.1
integrin.
3. The method according to claim 1 wherein said first and second
fibroblast cells each comprise a heparan sulfate sulfated
proteoglycan.
4. A method of screening for a modulator of cell migration
comprising the steps of: (a) forming a gel matrix comprising Cyr61
and a suspected modulator of cell migration; (b) preparing a
control gel matrix comprising Cyr61; (c) seeding fibroblast cells
presenting an .alpha..sub.6.beta..sub.1 integrin onto the gel
matrix of step (a) and the control gel matrix of step (b); (d)
incubating said fibroblast cells; (e) measuring the levels of cell
migration by inspecting the interior of said gel matrix and said
control gel matrix for cells; (f) comparing the levels of cell
migration measured in step (e), whereby a modulator of cell
migration is indentified by its ability to alter the level of cell
migration in the gel matrix when compared to the level of cell
migration in the control gel matrix.
5. The method according to claim 4 wherein said first and second
fibroblast cells comprise an .alpha..sub.6.beta..sub.1
integrin.
6. The method according to claim 4 wherein said first and second
fibroblast cells comprise a heparan-sulfate protoglycan.
7. The method according to claim 4 wherein said fibroblast cells
are human cells.
8. The method according to claim 4 wherein said matrix is selected
from the group consisting of Matrigel, collagen, and fibrin.
9. A method of screening for a modulator of fibroblast cell
proliferation comprising the steps of: (a) contacting a first
fibroblast cell presenting an .alpha..sub.6.beta..sub.1 integrin
with a suspected modulator and a biologically effective amount of
an ECM signaling molecule-related biomaterial selected from the
group consisting of a human Cyr61, a human Cyr61 fragment, a human
Cyr61 analog, and a human Cyr61 derivative; (b) separately
contacting a second fibroblast cell presenting an
.alpha..sub.6.beta..sub.1 integrin with a biologically effective
amount of an ECM signaling molecule-related biomaterial selected
from the group consisting of a human Cyr61, a human Cyr61 fragment,
a human Cyr61 analog, and a human Cyr61 derivative, thereby
providing a control; (c) incubating said first and second
fibroblast cells; (d) measuring the level of cell proliferation
resulting from step (c); and (e) comparing the levels of cell
proliferation measured in step (d), whereby a modulator of cell
proliferation is identified by its ability to alter the level of
cell proliferation when compared to the control of step (b).
10. The method according to claim 9 wherein said first and second
fibroblast cells comprise an .alpha..sub.6.beta..sub.1
integrin.
11. The method according to claim 9 wherein said first and second
fibroblast cells comprise a heparan sulfate proteoglycan.
12. A method of screening for a modulator of angiogenesis
comprising the steps of: (a) contacting a first endothelial cell
comprising a cyr61 allele with a suspected modulator of
angiogenesis; (b) measuring the Cyr61 activity of the first
endothelial cell; (c) measuring the Cyr61 activity of a second
endothelial cell comprising a cyr61 allele; and (d) comparing the
levels of Cyr61 activity measured in steps (b) and (c), thereby
identifying a modulator of angiogenesis.
13. A method of screening for a modulator of angiogenesis
comprising the steps of: (a) contacting a firt endothelial cell
with a polypeptide selected from the group consisting of a Cyr61, a
Fisp12, a CTGF, a NOV, and ELM-1 (WISP-1), a WISP-3, a COP-1
(WISP-2), and fragments, analogs, and derivatives of any of the
aforementioned members of the CCN family of proteins; (b) further
contacting the first endothelial cell with a suspected modulator of
angiogenesis; (c) contacting a second endothelial cell with the
polypeptide of step (a); (d) measuring the angiogenesis of the
first endothelial cell; (e) measuring the angiogenesis of the
second endothelial cell; and (f) comparing the levels of
angiogenesis measured in steps (d) and (e), thereby identifying a
modulator of angiogenesis.
14. A method of screening for modulators of angiogenesis comprising
the steps of: (a) constructing a transgenic animal comprising a
mutant allele of a gene encoding a polypeptide selected from the
group consisting of a Cyr61, a Fisp12, a CTGF, a NOV, an ELM-1
(WISP-1), a WISP-3, a COP-1 (WISP-2); (b) contacting the transgenic
animal with a suspected modulator of angiogenesis; (c) further
contacting a wild-type animal with said polypeptide, thereby
providing a control; (d) measuring the levels of angiogenesis in
the transgenic animal; (e) measuring the level of angiogenesis of
the wild-type animal; and (f) comparing the levels of angiogenesis
measured in steps (d) and (e), thereby identifying a modulator of
angiogenesis.
15. A method of screening for modulators of wound healing
comprising the steps of: (a) contacting a first activated platelet
with a polypeptide of the CCN family, such as Cyr61, and a
suspected modulator; (b) further contacting a second activated
platelet with the polypeptide of step (a); (c) measuring the
binding of the first activated platelet to the polypeptide; (d)
measuring the binding of the second activated platelet to the
polypeptide; and (e) comparing the binding measurements of steps
(d) and (e), thereby identifying a modulator of wound healing.
16. The method according to claim 15 wherein the platelets present
the .alpha..sub.llb.beta..sub.3 integrin.
17. A method of screening for modulators of macrophage adhesion
comprising the steps of: (a) contacting a first macrophage with a
Cyr61 and a suspected modulator; (b) further contacting a second
macrophage with said polypeptide of step (a); (c) measuring the
binding of the first macrophage to said polypeptide; (d) measuring
the binding of the second macrophage to said polypeptide; and (e)
comparing the binding measurements of steps (d) and (e), thereby
identifying a modulator of macrophage adhesion.
18. A mammalian cell comprising a cyr61 mutation selected from the
group consisting of an insertional inactivation of a cyr61 allele
and a deletion of a portion of a cyr61 allele.
19. The cell according to claim 18 wherein said mutation is a
homozygous mutation.
20. The cell according to claim 18 wherein said mutation is in the
coding region of cyr61.
21. The cell according to claim 18 wherein said cell is associated
with an organism.
22. The cell according to claim 18 wherein said cell is human.
23. The cell according to claim 18 wherein said cell is a
fibroblast.
24. An isolated human Cyr61 fragment comprising a sequence selected
from the group consisting of residues 280-290 of SEQ ID NO:33 and
residues 305-310 of SEQ ID NO:33, wherein said Cyr61 fragment
retains at least one biological function of human Cyr61.
25. The human Cyr61 fragment according to claim 24 comprising the
sequence set forth in SEQ ID NO:33 and retaining at least one
biological function of human Cyr61.
26. A human Cyr61 fragment comprising a sequence that is at least
95% similar to the sequence set forth in SEQ ID NO:33, wherein said
human Cyr61 fragment retains at least one biological function of
human Cyr61.
27. A humanCyr61 fragment encoded by a polynucleotide comprising a
sequence that is at least 95% similar to a polynucleotide encoding
a polypeptide having the sequence set forth at SEQ ID NO:33,
wherein said polypeptide retains at least one biological function
of human Cyr61.
28. A method for modulating gene expression comprising the step of
administering a biologically effective amount of a human Cyr61
fragment according to claim 24 to a cell capable of Cyr61-modulated
gene expression.
29. A method of screening for a modulator of binding between a
Cyr61 polypeptide and a Cyr61 receptor integrin selected from the
group consisting of .alpha..sub.V.beta..sub.3,
.alpha..sub.V.beta..sub.5, .alpha..sub.6.beta..sub.1,
.alpha..sub.ll.beta..sub.3 and .alpha..sub.M.beta..sub.3,
comprising the steps of: a) contacting a Cyr61 polypeptide with an
integrin receptor composition in the presence and in the absence of
a potential modulator compound; b) detecting binding between the
polypeptide and the integrin receptor; and c) identifying a
modulator compound in view of decreased or increased binding
between the Cyr61 and the integrin receptor in the presence of the
modulator, as compared to binding in the absence of the
modulator.
30. The method according to claim 29 wherein said Cyr61 polypeptide
lacks amino acid residues 282-381 of SEQ ID NO:4.
31. The method according to claim 29 wherein said Cyr61 receptor
integrin is .alpha..sub.V.beta..sub.3.
32. The method according to claim 29 wherein said Cyr61 receptor
integrin is .alpha..sub.V.beta..sub.5.
33. The method according to claim 29 wherein said Cyr61 receptor
integrin is .alpha..sub.6.beta..sub.1.
34. The method according to claim 29 wherein said Cyr61 receptor
integrin is .alpha..sub.ll.beta..sub.3.
35. The method according to claim 29 wherein said Cyr61 receptor
integrin is .alpha..sub.M.beta..sub.2.
36. A purified compound that is a modulator of binding between a
Cyr61 polypeptide and an integrin receptor, said compound
identified by the method according to claim 29.
37. The use of a modulator of a Cyr61-integrin
.alpha..sub.V.beta..sub.3 interaction for preparation of a
medicament for the treatment of a condition selected from the group
consisting of atherosclerosis, heart disease, tumor growth, tumor
metastasis, fibrosis, disorders associated with inadequate
angiogenesis, disorders associated with aberrant granulation tissue
development, aberrant fibroblast growth and wounds.
38. A method for treating a condition characterized by defective
connective tissue in a mammalian subject, comprising the steps of:
(a) identifying a mammalian subject in need of treatment for said
condition, and (b) administering to said mammalian subject a
composition comprising a modulator of an interaction between Cyr61
and an integrin receptor selected from the group consisting of
.alpha..sub.V.beta..sub.3, .alpha..sub.V.beta..sub.5,
.alpha..sub.6.beta..sub.1, .alpha..sub.ll.beta..sub.3 and
.alpha..sub.M.beta..sub.2, in an amount effective to mitigate the
symptoms of the condition in said mammalian subject.
39. The method according to claim 38 wherein said modulator is
selected from the group consisting of heparin, heparan sulfate and
a polypeptide that binds an integrin receptor.
40. The method according to claim 39 wherein said administering is
accomplished by expressing an exogenous polypeptide coding region
in cells of the type affected by said condition.
41. The method according to claim 39 wherein said polypeptide is a
fragment of a Cyr61 polypeptide.
42. The method according to claim 39 wherein said fragment of a
Cyr61 polypeptide comprises a sequence selected from the group
consisting of residues 280-290 of SEQ ID NO:4 and residues 306-312
of SEQ ID NO:4.
43. The method according to claim 38 wherein said condition
involves a defect in fibroblast adhesion and said integrin receptor
is .alpha..sub.b.beta..sub.1.
44. The method according to claim 38 wherein said condition
involves a defect in fibroblast chemotaxis and said integrin
receptor is .alpha..sub.V.beta..sub.5.
45. The method according to claim 38 wherein said condition
involves a defect in fibroblast proliferation and said integrin
receptor is .alpha..sub.V.beta..sub.3.
46. A method for treating a condition characterized by a defect in
smooth muscle tissue in a mammalian subject, comprising the steps
of: (a) identifying a mammalian subject in need of treatment for
said condition, and (b) administering to said mammalian subject a
composition comprising a modulator of an interaction between Cyr61
and an .alpha..sub.6.beta..sub.1 integrin receptor in an amount
effective to mitigate the symptoms of the condition in said
mammalian subject.
47. The method according to claim 46 wherein said modulator is
selected from the group consisting of heparin, heparan sulfate and
a polypeptide that binds an .alpha..sub.6.beta..sub.1 integrin
receptor.
48. The method according to claim 47 wherein said administering is
accomplished by expressing an exogenous polypeptide coding region
in cells of the type affected by said condition.
49. The method according to claim 46 wherein said polypeptide is a
fragment of Cyr61.
50. The method according to claim 48 wherein said fragment
comprises a sequence selected from the group consisting of residues
280-290 of SEQ ID NO:4 and residues 306-312 of SEQ ID NO:4.
51. The method according to claim 46 wherein said condition is
selected from the group consisting of atherosclerosis, heart
disease, tumor growth, tumor metastasis, fibrosis, disorders
associated with inadequate angiogenesis, disorders associated with
aberrant granulation tissue development, aberrant fibroblast growth
and wounds.
52. A kit for assaying for Cyr61-integrin receptor interactions,
said kit comprising a Cyr61 polypeptide and a composition
comprising an integrin receptor selected from the group consisting
of .alpha..sub.V.beta..sub.3, .alpha..sub.V.beta..sub.5,
.alpha..sub.6.beta..sub.1, .alpha..sub.ll.beta..sub.3 and
.alpha..sub.M.beta..sub.2.
53. The kit according to claim 52 wherein said integrin receptor
composition comprises an .alpha..sub.V.beta..sub.3 integrin
localized in a mammalian fibroblast cell membrane.
Description
FIELD OF THE INVENTION
[0001] The present invention is directed to materials and methods
involving extracellular matrix signaling molecules in the form of
polypeptides involved in cellular responses to growth factors. More
particularly, the invention is directed to Cyr6l-, Fisp12-, and
CTGF-related polynucleotides, polypeptides, compositions thereof,
methods of purifying these polypeptides, and methods of using these
polypeptides.
BACKGROUND OF THE INVENTION
[0002] The growth of mammalian cells istightlyregulated
bypolypeptide growth factors. In the adult animal, most cells are
metabolically active but are quiescent with regard to cell
division. Under certain conditions, these cells can be stimulated
to reenter the cell cycle and divide. As quiescent cells reenter
the active growth and division phases of the cell cycle, a number
of specific genes, the immediate early genes, are rapidly
activated. Reentry to the active cell cycle is by necessity tightly
regulated, since a breakdown of this control can result in
uncontrolled growth, frequently recognized as cancer. Controlled
reentry of particular cells into the growth phase is essential for
such biological processes as angiogenesis (e.g., blood vessel
growth and repair), chondrogenesis (e.g., skeletal development and
prosthesis integration), oncogenesis (e.g., cancer cell metastasis
and tumor neovascularization), and other growth-requiring
processes.
[0003] Angiogenesis, the formation of new blood vessels from the
endothelial cells of preexisting blood vessels, is a complex
process which involves a changing profile of endothelial cell gene
expression, associated with cell migration, proliferation, and
differentiation. Angiogenesis begins with localized breakdown of
the basement membrane of the parent vessel. In vivo, basement
membranes (primarily composed of laminin, collagen type IV,
nidogen/entactin, and proteoglycan) support the endothelial cells
and provide a barrier separating these cells from the underlying
stroma. The basement membrane also affects a variety of biological
activities including cell adhesion, migration, and growth during
development and differentiation.
[0004] Following breakdown of the basement membrane, endothelial
cells migrate away from the parent vessel into the interstitial
extracellilar matrix (ECM), at least partially due to
chemoattractant gradients. The migrating endothelial cells form a
capillary sprout, which elongates. This elongation is the result of
migration and proliferation of cells in the sprout. Cells located
in the leading capillary tip migrate toward the angiogenic
stimulus, but neither synthesize DNA nor divide. Meanwhile, behind
these leading tip cells, other endothelial cells undergo rapid
proliferation to ensure an adequate supply of endothielial cells
for formation of the new vessel. Capillary sprouts then branch at
their tips, the branches anastomose or join with one another to
form a lumen, the basement membrane is reconstituted, and a
vascular connection is established leading to blood flow.
[0005] Alterations in at least three endothelial cell functions
occur during angiogenesis: 1) modulations of interactions with the
ECM, which require alterations of cell-matrix contacts and the
production of matrix-degrading proteolytic enzymes; 2) an initial
increase and subsequent decrease in endothelial cell migration,
effecting cell translocation towards an angiogenic stimulus; and 3)
a transient increase in cell proliferation, providing cells for the
growing and elongating vessel, with a subsequent return to the
quiescent cell state once the vessel is formed These three
functions are realized by adhesive, chemotactic, and mitogenic
interactions or responses, respectively. Therefore, control of
angiogenesis requires intervention in three distinct cellular
activities:. 1) cell adhesion, 2) cell migration, and 3) cell
proliferation. Another biological process involving a similar
complex array of cellular activities is chondrogenesis.
[0006] Chondrogenesis is the cellular process responsible for
skeletal organization, including the development of bone and
cartilage. Chondrogenesis, like angiogenesis, involves the
controlled reentry of quiescent cells into the growth phase of the
cell cycle. The growth phase transition is associated with altered
cell adhesion characteristics, changed patterns of cell migration,
and transiently increased cell proliferation. Chondrogenesis
involves the initial development of chondrogenic capacity (i.e.,
the proto-differentiated state) by primitive undifferentiated
mesenchyme cells. This stage involves the production of
chondrocyte-specific markers without the ability to produce a
typical cartilage ECM. Subsequently, the cells develop the
capacitytoproduce acartilage-specific ECM as they differentiate
into chondrocytes. Langille, Microscop. Res. & Tech. 28:455-469
(1994). Chondrocyte migration, adhesion, and proliferation then
contribute to the development of bony, and cartilaginous, skeleton.
Abnormal elaboration of the programmed development of cells
participating in the process of chondrogenesis results in skeletal
defects presenting problems that range from cosmetic concerns to
life-threatening disorders.
[0007] Like angiogenesis and chondrogenesis, oncogenesis is
characterized by changes in cell adhesion, migration, and
proliferation. Metastasizing cancer cells exhibit altered adhesion
and migration properties. Establishment of tumorous masses requires
increased cell proliferation and the elaboration of the cellular
properties characteristic of angiogenesis during the
neovascularization of tumors.
[0008] Abnormal progression of angiogenesis orchondrogenesis, as
well as mere progression of oncogenesis, substantially impairs the
quality of life for afflicted individuals and adds to modern health
care costs. The features common to these complex biological
processes, comprising altered cell adhesion, migration, and
proliferation, suggest that agents capable of influencing all three
of these cellular activities would be effective in screening for,
and modulating, the aforementioned complex biological processes.
Although the art is aware of agents that influence individual
cellular activities, e.g., integrins and selectins (cell adhesion),
chemokines (cell migration), and a variety of growth factors or
cytokines (cell proliferation), until recently no agent has been
identified that exerts an influence over all three cellular
activities in humans.
[0009] Murine Cyr61 (CYsteine-Rich protein) is a protein expressed
in actively growing and dividing cells that may influence each of
these three cellular activities. RNase protection analyses have
shown that the gene encoding murine Cyr61, murine cyr61, is
transcribed in the developing mouse embryo. O'Brien et al., Cell
Growth & Diff. 3:645-654 (1992). In situ hybridization analysis
showed that expression of cyr61 during mouse embryogenesis is
closely correlated with the differentiation of mesenchymal cells,
derived from ectoderm and mesoderm, into chondrocytes. In addition,
cyr61 is expressed in the vessel walls of the developing
circulatory system. These observations indicate that murine cyr61
is expressed during cell proliferation and differentiation, which
are characteristics of expression ofgenes involved in regulatory
cascades that control the cell growth cycle.
[0010] Further characterization of the Cyr61 polypeptide has been
hampered by an inability to purify useful quantities of the
protein. Efforts to purify Cyr61 in quantity by overexpression from
either eukaryotic or prokaryotic cells typically fail. Yang,
University of Illinois at Chicago, Ph. D. Thesis (1993). One
problem associated with attempting to obtain useful quantities of
Cyr61 is the reduction in mammalian growth rates induced by
overexpression of Cyr61. Another problem with Cyr61 purification is
that the cysteine-rich polypeptide, when expressed in bacterial
cells using recombinant DNA techniques, is often found in insoluble
protein masses. Nevertheless, Cyr61 has been characterized as a
polypeptide of 349 amino acids, containing 39 cysteine residues, a
hydrophobic putative N-terminal signal sequence, and potential
N-linked glycosylation sites (Asn.sub.28 and Asn.sub.225). U.S.
Pat. No. 5,408,040 at column 3, lines 41-54, Grotendorst et al.,
incorporated herein by reference (the '040 Patent). Recently,
proteins related to Cyr61 have been characterized. For example, a
human protein, Connective Tissue Growth Factor (CTGF), has been
identified. (See '040 Patent). CTGF is expressed in actively
growing cells such as fibroblasts and endothelial cells ('040
Patent, at column 5, lines 62-64), an expression pattern shared by
Cyr61. In terms of function, CTGF has been described as a protein
growth factor because its primary biological activity has been
alleged to be its mitogenicity ('040 Patent, at column 2, lines
25-27 and 53-55). In addition, CTGF reportedly exhibits chemotactic
activity. '040 Patent, at column 2, lines 56-59. In terms of
structure, the polynucleotide sequence encoding CTGF, and the amino
acid sequence of CTGF, have been published. '040 Patent, SEQ ID
NO:7 and SEQ ID NO:8, respectively.
[0011] Another apparently related protein is the mouse protein
Fisp12 (FIbroblast Secreted Protein). Fisp12 has been subjected to
amino acid sequence analysis, revealing a primary structure that is
rich in cysteines. Ryseck et al., Cell Growth & Diff 2:225-233
(1991), incorporated herein by reference. The protein also
possesses a hydrophobic N-terminal sequence suggestive of the
signal sequence characteristic of secreted proteins.
[0012] Sequence analyses involving Cyr61, Fisp12, CTGF, and other
proteins, have contributed to the identification of a family of
cysteine-rich secreted proteins. Members of the family share
similar primary structures encoded by genes exhibiting similar
sequences. Each of the proteins in this emerging family is further
characterized by the presence of a hydrophobic N-terminal signal
sequence and 38 cysteine residues in the secreted forms of the
proteins. Members of the family identified to date include the
aforementioned Cyr61 (human and mouse), Fisp12 (mouse), and CTGF
(the human ortholog of Fisp12), as well as CEF10 (chicken), and Nov
(avian).
[0013] One of several applications for a purified protein able to
affect cell adhesion, migration, and proliferation properties
involves the development of stable, long term ex vivo hematopoietic
stem cell cultures. Patients subjected to high-dose chemotherapy
have suppressed hematopoiesis; expansion of stem cells, their
maturation into various hematopoietic lineages, and mobilization of
mature cells into circulating blood routinely take many weeks to
complete. For such patients, and others who need hematopoietic cell
transplantation, introduction into those patients of autologous
stem cells that have been manipulated and expanded in culture is
advantageous. Such hematopoictic stem cells (HSC) express the CD34
stem cell antigen, but do not express lineage commitment antigens.
These cells can eventually give rise to all blood cell lineages
(e.g., erythrocytes, lymphocytes, and myelocytes). Hematopoietic
progenitor cells that can initiate and sustain long term cultures
(i.e., long term culture system-initiating cells or LTC-IC)
represent a primitive population of stem cells. The frequency of
LTC-IC has been estimated at only 1-2 per 10.sup.4 cells in normal
human marrow and only about 1 per 50-100 cells in a highly purified
CD34.sup.+ subpopulation. Thus, it would be useful to have methods
and systems for long term cell culture that maintain and expand
primitive, pluripotent human HSC to be used for repopulation of the
hematopoietic system in vivo.
[0014] Cell culture models of hematopoiesis have revealed a
multitude of cytokines that appear to play a role in the
hematopoictic process, including various colony stimulating
factors, interleukins, stem cell factor, and the c-kit ligand.
However, in ex vivo cultures, different combinations of these
cytokines favor expansion ofdifferent sets ofcommitted progenitors.
For example, a factor in cord blood plasma enhanced expansion of
granulocyte-erythroid-macrophage-megakaryocyte colony forming unit
(CFU-GEMM) progenitors, but expansion in these cultures favored the
more mature subsets of cells. Therefore, it has been difficult to
establish a culture system that mimics in vivo hematopoiesis.
[0015] An HSC culture system should maintain and expand a large
number of multi- or pluripotent stem cells capable of both long
term repopulation and eventual lineage commitment under appropriate
induction. However, in most ex vivo culture systems, the fraction
of the cell population comprised of LTC-IC decreases steadily with
continued culturing, often declining to 20% of their initial level
after several weeks, as the culture becomes populated by more
mature subsets of hematopoietic progenitor cells that are no longer
pluripotent. Moreover, the proliferative capacity exhibited by
individual LTC-IC may vary extensively. Thus, a need exists in the
art for HSC culture systems comprising biological agents that
maintain or promote the pluripotent potential of cells such as
LTC-IC cells. In addition to a role in developing ex vivo HSC
cultures, biological agents affecting cell adhesion, migration, and
proliferation are useful in a variety of other contexts.
[0016] Proteins that potentiate the activity of mitogens but have
no mitogenic activity themselves may play important roles as
signaling molecules in such processes as hematopoiesis. Moreover,
these signaling proteins could also serve as probes in the search
for additional mitogens, many of which have not been identified or
characterized. Several biological factors have been shown to
potentiate the mitogenic activity of other factors, without being
mitogenic themselves. Some of these potentiators are associated
with the cell surface and/or extracellular matrix. Included in this
group are a secreted basic Fibroblast Growth Factor-binding protein
(bFGF-binding protein), the basal lamina protein perlecan, and the
Human Immunodeficiency Viris-1 TAT protein, each protein being able
to promote bFGF-induced cell proliferation and angiogenesis. Also
included in this group of mitogen potentiators are thrombospondin,
capable of activating a latent form of Transforming Growth
Factor-.beta., and an unidentified secreted growth-potentiating
factor from vascular smooth muscle cells (Nakano et al. J. Biol.
Chem. 270:5702-5705 [1995]), the latter factor being required for
efficient activation of Epidermal Growth Factor- or
thrombin-induced DNA synthesis. Further, the B cell stimulatory
factor-1/interleukin-4, a T cell product with no demonstrable
mitogenic activity, is able to 1) enhance the proliferative
response of granulocyte-macrophage progenitors to
granulocyte-colony stimulating factor, 2) enhance the proliferative
response of erythroid progenitors to erythropoietin, and 3)
together with erythropoietin, induce colony formation by
multipotent progenitor cells. Similarly, interleukin-7 enhanced
stem cell factor-induced colony formation by primitive murine bone
marrow progenitors, although interleukin-7 had no proliferative
effect by itself. In addition, lymphocyte growth enhancing factor
(LGEF) was found to enhance mitogen-stimulated human peripheral
blood lymphocyte (PBL) or purified T cell proliferation in a
dose-dependenit fashion. LGEF alone did not stimulate PBL or T cell
proliferation.
[0017] Therefore, a need continues to exist for biological agents
capable of exerting a concerted and coordinated influence on one or
more of the particularized functions (e.g., cell adhesion, cell
migration and cell proliferation) collectively characterizing such
complex biological processes as angiogenesis, chondrogenesis, and
oncogenesis. In addition, a need persists in the art for agents
contributing to the reproduction of these in vivo processes in an
ex vivo environment, e.g., the development of HSC cultures.
Further, there continues to be a need for tools to search for the
remaining biological components of these complex processes, e.g.,
mitogen probes, the absence of which impedes efforts to
advantageously modulate and thereby control such processes.
SUMMARY OF THE INVENTION
[0018] The present invention provides extracellular matrix (ECM)
signaling molecule-related materials and methods. In particular,
the present invention is directed to polynucleotides encoding ECM
signaling molecules and fragments or analogs thereof, ECM signaling
molecule-related polypeptides and fragments, analogs, and
derivatives thereof, methods of producing ECM signaling molecules,
methods of using ECM signaling molecules, methods of screening for
modulators of an ECM signaling molecule activity, those modulators,
and methods of using those modulators to treat diseases or
conditions related to angiogenesis, chondrogenesis, oncogenesis,
cell migration, cell adhesion and cell proliferation.
[0019] One aspect of the present invention relates to a purified
and isolated polypeptide comprising an ECM signaling molecule. The
polypeptides according to the invention retain at least one
biological activity of an ECM signaling molecule, such as the
ability to stimulate cell adhesion, cell migration, or cell
proliferation; the ability to modulate angiogenesis,
chondrogenesis, or oncogenesis; immunogenicity or the ability to
elicit an immune response; and the ability to bind to polypeptides
having specific binding sites for ECM signaling molecules,
including antibodies and integrins. The polypeptides may be native
or recombinant molecules. Further, the invention comprehends
full-length ECM signaling molecules, and fragments thereof, such as
an isolated human Cyr61 fragment comprising a sequence selected
from the group consisting of residues 280-290 of SEQ ID NO:33 and
residues 305-310 of SEQ ID NO:33, wherein said Cyr61 fragment
retains at least one biological function of human Cyr61. Of course,
the human Cyr61 fragment may comprise the sequence set forth in SEQ
ID NO:33, provided such a fragment, like all of the fragments of
the invention, retains at least one biological function of human
Cyr61. More generally, the human Cyr61 fragment may comprise a
sequence that is at least 95% similar to the sequence set forth in
SEQ ID NO:33, wherein the human Cyr61 fragment again retains at
least one biological function of human Cyr61. Human Cyr61 fragments
contemplated by the invention may be encoded by a polynucleotide
comprising a sequence that is at least 95% similar (using BLAST
software as described with default settings) to a polynucleotide
encoding a polypeptide having the sequence set forth at SEQ ID
NO:33, wherein said polypeptide retains at least one biological
function of human Cyr61. In addition, the polypeptides of the
invention may be underivatized, or derivatized in conformity with a
native or non-native derivatization pattern. The invention further
extends to polypeptides having a native or naturally occurring
amino acid sequence, and variants (i.e., polypeptides having
different amino acid sequences), analogs (i.e., polypeptides having
a non-standard amino acid or other structural variation from the
conventional set of amino acids) and homologs (i.e., polypeptides
sharing a common evolutionary ancestor with another polypeptide)
thereof. Polypeptides that are covalently linked to other
compounds, such as polyethylene glycol, or other proteins or
peptides, i.e., fusion proteins, are contemplated by the
invention.
[0020] Exemplary ECM signaling molecules include mammalian Cyr61,
Fisp12, and CTGF polypeptides. Beyond ECM signaling molecules, the
invention includes polypeptides that specifically bind an ECM
signaling molecule of the invention, such as the aforementioned
antibody products. A wide variety of antibody products fall within
the scope of the invention, including polyclonal and monoclonal
antibodies, antibody fragments, chimeric antibodies, CDR-grafted
antibodies, "humanized" antibodies, and other antibody forms known
in the art. Other molecules such as peptides, carbohydrates or
lipids designed to bind to an active site of the ECM molecules
thereby inhibiting their activities are also contemplated by the
invention. However molecules such as peptides that enhance or
potentiate the activities of ECM molecule are also within the scope
of the invention. The invention further extends to a pharmaceutical
composition comprising a biologically effective amount of a
polypeptide and a pharmaceutically acceptable adjuvant, diluent or
carrier, according to the invention. A "biologically effective
amount" of the biomaterial is an amount that is sufficient to
result in a detectable response in the biological sample when
compared to a control lacking the biomaterial.
[0021] Another aspect of the invention relates to a purified and
isolated polynucleotide comprising a sequence that encodes a
polypeptide of the invention. A polynucleotide according to the
invention may be DNA or RNA, single- or double-stranded, and may be
may purified and isolated from a native source, or produced using
synthetic or recombinant techniques known in the art. The invention
also extends to polynucleotides encoding fragments, analogs (i.e.,
polynucleotides having a non-standard nucleotide), homologs (i.e.,
polynucleotides having a common evolutionary ancestor with another
polynucleotide), variants (i.e., polynucleotides differing in
nucleotide sequence), and derivatives (i.e., polynucleotides
differing in a structural manner that does not involve the primary
nucleotide sequence) of ECM molecules. Vectors comprising a
polynucleotide according to the invention are also contemplated. In
addition, the invention comprehends host cells transformned or
transfected with a polynucleotide or vector of the invention.
[0022] In a related aspect, the invention contemplates a mammalian
cell comprising a cyr61 mutation selected from the group consisting
of an insertional inactivation of a cyr61 allele and a deletion of
a portion of a cyr61 allele. The mammalian cell is preferably a
human cell and the mutation is either heterozygous or homozygous.
The mutation, resulting from insertional inactivation or deletion,
is either in the coding region or a flanking region essential for
expression such as a 5' promoter region. Cells are also found
associated with non-human animals.
[0023] Other aspects of the invention relate to methods for making
or using the polypeptides and/or polynucleotides of the invention.
A method for making a polypeptide according to the invention
comprises expressing a polynucleotide encoding a polypeptide
according to the present invention in a suitable host cell and
purifying the polypeptide. Other methods for making a polypeptide
of the invention use techniques that are known in the art, such as
the isolation and purification of native polypeptides or the use of
synthetic techniques for polypeptide production. In particular, a
method of purifying an ECM signaling molecule such as human Cyr61
comprises the steps of identifying a source containing human Cyr61,
exposing the source to a human Cyr61-specific biomolecule that
binds Cyr61 such as an anti-human Cyr61 antibody, and eluting the
human Cyr61 from the antibody or other biomolecule, thereby
purifying the human Cyr61.
[0024] Another aspect of the invention is a method of screening for
a modulator of angiogenesis comprising the steps of: (a) contacting
a first biological sample capable of undergoing angiogenesis with a
biologically effective (i.e., angiogenically effective) amount of
an ECM signaling molecule-related biomaterial and a suspected
modulator (inhibitor or potentiator); (b) separately contacting a
second biological sample with a biologically effective amount of an
ECM signaling molecule-related biomaterial, thereby providing a
control; (c) measuring the level of angiogenesis resulting from
step (a) and from step (b); and (d) comparing the levels of
angiogenesis measured in step (c), whereby a modulator of
angiogenesis is identified by its ability to alter the level of
angiogenesis when compared to the control of step (b). The
modulator may be either a potentiator or inhibitor of angiogenesis
and the ECM signaling molecule-related biomaterial includes, but is
not limited to, Cyr61, and fragments, variants, homologs, analogs,
derivatives, and antibodies thereof.
[0025] The invention also extends to a method of screening for a
modulator of angiogenesis comprising the steps of: (a) preparing a
first implant comprising Cyr61 and a second implant comprising
Cyr61 and a suspected modulator of Cyr61 angiogenesis; (b)
implantling the first implant in a first cornea of a test animal
and the second implant in a second cornea of the test animal; (c)
measuring the development of blood vessels in the first and second
corneas; and (d) comparing the levels of blood vessel development
measured in step (c), whereby a modulator of angiogenesis is
identified by its ability to alter the level of blood vessel
development in the first cornea when compared to the blood vessel
development in the second cornea.
[0026] Another aspect of the invention is a method of screening for
a modulator of angiogeniesis comprising the steps of: (a)
contacting a first endothelial cell comprising a cyr61 allele with
a suspected modulator of angiogenesis; (b) measuring the Cyr61
activity of the first endothelial cell; (c) measuring the Cyr61
activity of a second endothelial cell comprising a cyr61 allele;
and (d) comparing the levels of Cyr61 activity measured in steps
(b) and (c), thereby identifying a modulator of angiogenesis. A
related aspect of the invention is drawn to a method of screening
for a modulator of angiogenesis comprising the steps of: (a)
contacting a first endothelial cell with a polypeptide selected
from the group consisting of a Cyr61, a Fisp12, a CTGF, a NOV, an
ELM-1 (WISP-1), a WISP-3, a COP-1 (WISP-2), and fragments, analogs,
and derivatives of any of the aforementioned polypeptides, which
are members of the CCN family of proteins; (b) further contacting
the first endothelial cell with a suspected modulator of
angiogenesis; (c) contacting a second endothelial cell with the
polypeptide of step (a); (d) measuring the angiogenesis of the
first endothelial cell; (c) measuring the angiogenesis of the
second endothelial cell; and (f) comparing the levels of
angiogenesis measured in steps (d) and (e), thereby identifying a
modulator of angiogenesis.
[0027] Yet another related aspect of the invention is a method of
screening for modulators of angiogenesis comprising the steps of:
(a) constructing a transgenic animal comprising a mutant allele of
a gene encoding a polypeptide selected from the group consisting of
a Cyr61, a Fisp12, a CTGF, a NOV, an ELM-1 (WISP-1), a WISP-3, a
COP-1 (WISP-2); (b) contacting the transgenic animal with a
suspected modulator of angiogenesis; (c) further contacting a
wild-type animal with the polypeptide, thereby providing a control;
(d) measuring the levels of angiogenesis in the transgenic animal;
(e) measuring the level of angiogenesis of the wild-type animal;
and (f) comparing the levels of angiogeniesis measured in steps (d)
and (e), thereby identifying a modulator of angiogenesis.
[0028] Another aspect of the invention relates to a method of
screening for a modulator of chondrogenesis comprising the steps
of: (a) contacting a first biological sample capable of undergoing
chondrogeniesis with a biologically effective (e.g.
chondrogenically effective) amount of an ECM signaling
molecule-related biomaterial and a suspected modulator; (b)
separately contacting a second biological sample capable of
undergoing chondrogenesis with a biologically effective amount of
an ECM signaling molecule-related biomaterial, thereby providing a
control; (c) measuring the level of chondrogenesis resulting from
step (a) and from step (b); and (d) comparing the levels of
chondrogenesis measured in step (c), whereby a modulator of
chondrogenesis is identified by its ability to alter the level of
chondrogenesis when compared to the control of step (b). The
modulator may be either a promoter or an inhibitor of
chondrogenesis; the ECM signaling molecules include those defined
above and compounds such as mannose-6-phosphate, heparin, and
tenascin.
[0029] The invention also relates to an in vitro method of
screening for a modulator of oncogenesis comprising the steps of:
(a) inducing a first tumor and a second tumor; (b) administering a
biologically effective amount of an ECM signaling molecule-related
biomaterial and a suspected modulator to the first tumor; (c)
separately administering a biologically effective amount of an ECM
signaling molecule-related biomaterial to the second tumor, thereby
providing a control; (d) measuring the level of oncogenesis
resulting from step (b) and from step (c); and (e) comparing the
levels of oncogenesis measured in step (d), whereby a modulator of
oncogenesis is identified by its ability to alter the level of
oncogenesis when compared to the control of step (c). Modulators of
oncogenesis contemplated by the invention include inhibitors of
oncogenesis. Tumors may be induced by a variety of techniques
including, but not limited to, the administration of chemicals,
e.g., carcinogens, and the implantation of cancer cells. A related
aspect of the invention is a method for treating a solid tumor
comprising the step of delivering a therapeutically effective
amount of a Cyr61 inhibitor to an individual, thereby inhibiting
the neovascularization of the tumor. Inhibitors include, but are
not limited to, inhibitor peptides such as peptides having the
"RGD" motif, and cytotoxins, which may be free or attached to
molecules such as Cyr61.
[0030] Yet another aspect of the invention is directed to a method
of screening for a modulator of cell adhesion comprising the steps
of: (a) preparing a surface compatible with cell adherence; (b)
separately placing first and second biological samples capable of
undergoing cell adhesion on the surface; (c) contacting a first
biological sample with a suspected modulator and a biologically
effective amount of an ECM signaling molecule-related biomaterial
selected from the group consisting of a human Cyr61, a human Cyr61
fragment, a human Cyr61 analog, and a human Cyr61 derivative; (d)
separately contacting a second biological sample with a
biologically effective amount of an ECM signaling molecule-related
biomaterial selected from the group consisting of a human Cyr61, a
human Cyr61 fragment, a human Cyr61 analog, and a human Cyr61
derivative, thereby providing a control; (c) measuring the level of
cell adhesion resulting from step (c) and from step (d); and (f)
comparing the levels of cell adhesion measured in step (e), whereby
a modulator of cell adhesion is identified by its ability to alter
the level of cell adhesion when compared to the control of step
(d).
[0031] In a related aspect, the invention provides a method of
screening for a modulator of cell adhesion comprising the steps of:
(a) contacting a first fibroblast cell with a suspected modulator
of cell adhesion and a biologically effective amount of an ECM
signaling molecule-related biomaterial selected from the group
consisting of a Cyr61, a Fisp12, a CTGF, a NOV, an ELM-1 (WISP-1),
a WISP-3, a COP-1 (WISP-2), and fragments, analogs, and derivatives
of any of the aforementioned members of the CCN family of proteins;
(b) separately contacting a second fibroblast cell with a
biologically effective amount of an ECM signaling molecule-related
biomaterial described above, thereby providing a control; (c)
measuring the level of cell adhesion resulting from step (a) and
from step (b); and (d) comparing the levels of cell adhesion
measured in step (c), whereby a modulator of cell adhesion is
identified by its ability to alter the level of cell adhesion when
compared to the control of step (h). In a preferred embodiment of
the method, the fibroblast cells present the
.alpha..sub.6.beta..sub.1 integrin. Also preferred are fibroblast
cells that present a sulfated proteoglycan, such as a heparan
sulfate proteoglycan or a chondroitin sulfate proteoglycan.
[0032] Yet another aspect of the invention is a method of screening
for modulators of macrophage adhesion comprising the steps of: (a)
contacting a first macrophage with a polypeptide of the CCN family,
such as Cyr61, and a suspected modulator; (b) further contacting a
second macrophage with the polypeptide of step (a); (c) measuring
the binding of the first macrophage to the polypeptide; (d)
measuring the binding of the second macrophage to the polypeptide;
and (e) comparing the binding measurements of steps (d) and (e),
thereby identifying a modulator of macrophage adhesion. Analogous
methods of the invention are used to screen for modulators of an
inflammatory response.
[0033] The invention also extends to a method of screening for a
modulator of cell migration comprising the steps of: (a) forming a
gel matrix comprising Cyr61 and a suspected modulator of cell
migration; (b) preparing a control gel matrix comprising Cyr61; (c)
seeding endothelial cells capable of undergoing cell migration onto
the gel matrix of step (a) and the control gel matrix of step (b);
(d) incubating the endothelial cells; (e) measuring the levels of
cell migration by inspecting the interior of the gel matrix and the
control gel matrix for cells; (f) comparing the levels of cell
migration measured in step (e), whereby a modulator of cell
migration is identified by its ability to alter the level of cell
migration in the gel matrix when compared to the level of cell
migration in the control gel matrix. The endothelial cells include,
but are not limited to, human cells, e.g., human microvascular
endothelial cells. The matrix may be formed from gelling materials
such as Matrigel, collagen, or fibrin, or combinations thereof.
[0034] In a related aspect, the invention comprehends a method of
screening for modulators of fibroblast cell migration comprising
the steps of: (a) contacting a first fibroblast cell with a
suspected modulator of cell migration and a biologically effective
amount of an ECM signaling molecule-related biomaterial selected
from the group consisting of a Cyr61, a Fisp12, a CTGF, a NOV, an
ELM-1 (WISP-1), a WISP-3, a COP-1 (WISP-2), and fragments, analogs,
and derivatives of any of the aforementioned members of the CCN
family of proteins; (b) separately contacting a second fibroblast
cell with a biologically effective amount of an ECM signaling
molecule-related biomaterial described above, thereby providing a
control; (c) measuring the level of cell migration resulting from
step (a) and from step (b); and (d) comparing the levels of cell
migration measured in step (c), whereby a modulator of cell
migration is identified by its ability to alter the level of cell
migration when compared to the control of step (b). Preferred
embodiments of the methods of screening for modulators of cell
migration involve the use of fibroblasts presenting an
.alpha..sub.6.beta..sub.1 integrin and/or a sulfated
proteoglycan.
[0035] Another aspect of the invention is directed to an in vitro
method of screening for cell migration comprising the steps of: (a)
forming a first gelatinized filter and a second gelatinized filter,
each filter having two sides; (b) contacting a first side of each
the filter with endothelial cells, thereby adhering the cells to
each the filter; (c) applying an ECM signaling molecule and a
suspected modulator of cell migration to a second side of the first
gelatinized filter and an ECM signaling molecule to a second side
of the second gelatinized filter; (d) incubating each the filter;
(e) detecting cells on the second side of each the filter; and (f)
comparing the presence of cells on the second side of the first
gelatinized filter with the presence of cells on the second side of
the second gelatinized filter, whereby a modulator of cell
migration is identified by its ability to alter the level of cell
migration measured on the first gelatinized filter when compared to
the cell migration measured on the second gelatinized filter. The
endothelial cells are defined above. The ECM signaling molecules
extend to human Cyr61 and each of the filters may be placed in
apparatus such as a Boyden chamber, including modified Boyden
chambers.
[0036] The invention also embraces an in vivo method of screening
for a modulator of cell migration comprising the steps of: (a)
removing a first central portion of a first biocompatible sponge
and a second central portion of a second biocompatible sponge; (b)
applying an ECM signaling molecule and a suspected modulator to the
first central portion and an ECM signaling molecule to the second
central portion; (c) reassociating the first central portion with
said first biocompatible sponge and said second central portion
with the second biocompatible sponge; (d) attaching a first filter
to a first side of the first biocompatible sponge and a second
filter to a second side of the first biocompatible sponge; (e)
attaching a third filter to a first side of the second
biocompatible sponge and a fourth filter to a second side of the
second biocompatible sponge; (f) implanting each of the
biocompatible sponges, each biocompatible sponge comprising the
central portion and the filters, in a test animal; (e) removing
each the sponge following a period of incubation; (f) measuring the
cells found within each of the biocompatible sponges; and (g)
comparing the presence of cells in the first biocompatible sponge
with the presence of cells in the second biocompatible sponge,
whereby a modulator of cell migration is identified by its ability
to alter the level of cell migration measured using the first
biocompatible sponge when compared to the cell migration measured
using the second biocompatible sponge. ECM signaling molecules
include, but are not limited to, human Cyr61; the ECM signaling
molecule may also be associated with Hydron. In addition, the in
vivo method of screening for a modulator of cell migration may
include the step of providing a radiolabel to the test animal and
detecting the radiolabel in one or more of the sponges.
[0037] Another aspect of the invention relates to a method for
modulating hemostasis comprising the step of administering an ECM
signaling molecule in a phanmaceultically acceptable adjuvant,
diluent or carrier. Also, the invention extends to a method of
inducing wound healing in a tissue comprising the step of
contacting a wounded tissue with a biologically effective amount of
an ECM signaling molecule, thereby promoting wound healing. The ECM
signaling molecule may be provided in the form of an ECM signaling
molecule polypeptide or an ECM signaling molecule nucleic acid,
e.g., using a gene therapy technique. For example, the nucleic acid
may comprise an expression control sequence operably linked to an
ECM signaling molecule which is then introduced into the cells of a
wounded tissue. The expression of the coding sequence is
controlled, e.g., by using a tissue-specific promoter such as the
K14 promoter operative in skin tissue to effect the controlled
induction of wound healing. The nucleic acid may include a vector
such as a Herpesvirus, an Adenovirus, an Adeno-associated Virus, a
Cytomegalovinis, a Baculovirus, a retrovirus, and a Vaccinia Virus.
Suitable wounded tissues for treatment by this method include, but
are not limited to, skin tissue and lung epithelium.
[0038] A related method comprises administering a biologically
effective amount of an ECM signaling molecule, e.g. Cyr61, to an
animal to promote organ regeneration. The impaired organ may be the
result of trauma, e.g. surgery, or disease. Another method of the
invention relates to improving the vascularization of grafts, e.g.,
skin grafts. Another method of the invention is directed to a
process for promoting bone implantation, including bone grafts. The
method for promoting bone implantation comprises the step of
contacting a bone implant or receptive site with a biologically
effective (i.e., chondrogenically effective) amount of an ECM
signaling molecule. The contacting step may be effected by applying
the ECM signaling molecule to a biocompatible wrap such as a
biodegradable gauze and contacting the wrap with a bone implant,
thereby promoting bone implantation. The bone implants comprise
natural bones and fragments thereof, as well as inanimate natural
and synthetic materials that are biocompatible, such as prostheses.
In addition to direct application of an ECM signaling molecule to a
bone, prosthesis, or receptive site, the invention contemplates the
use of matrix materials for controlled release of the ECM signaling
molecule, in addition to such application materials as gauzes.
[0039] Still another related aspect of the invention is a method of
screening for modulators of wound healing comprising the steps of:
(a) contacting a first activated platelet with a polypeptide of the
CCN family, such as Cyr61, and a suspected modulator; (b) further
contacting a second activated platelet with the polypeptide of step
(a); (c) measuring the binding of the first activated platelet to
the polypeptide; (d) measuring the binding of the second activated
platelet to the polypeptide; and (e) comparing the binding
measurements of steps (d) and (e), thereby identifying a modulator
of wound healing. Preferably, the wound healing involves the
participation of platelet binding in the process of blood clotting.
Also preferred are platelets presenting the
.alpha..sub.11b.beta..sub.3 integrin.
[0040] Yet another aspect of the invention relates to a method of
screening for a modulator of cell proliferation comprising the
steps of: (a) contacting a first biological sample capable of
undergoing cell proliferation with a suspected modulator and a
biologically effective (i.e., mitogenically effective) amount of an
ECM signaling molecule-related biomaterial selected from the group
consisting of a human Cyr61, a human Cyr61 fragment, a human Cyr61
analog, and a human Cyr61 derivative; (b) separately contacting a
second biological sample capable of undergoing cell proliferation
with a biologically effective amount of an ECM signaling
molecule-related biomaterial selected from the group consisting of
a human Cyr61, a human Cyr61 fragment, a human Cyr61 analog, and a
human Cyr61 derivative, thereby providing a control; (c) incubating
the first and second biological samples; (d) measuring the level of
cell proliferation resulting from step (c); and (e) comparing the
levels of cell proliferation measured in step (d), whereby a
modulator of cell proliferation is identified by its ability to
alter the level of cell adhesion when compared to the control of
step (b).
[0041] In a related aspect, the invention contemplates a method of
screening for modulators of fibroblast cell proliferation
comprising the steps of: (a) contacting a first fibroblast cell
with a suspected modulator of cell proliferation and a biologically
effective amount of an ECM signaling molecule-related biomaterial
selected from the group consisting of a Cyr61, a Fisp12, a CTGF, a
NOV, an ELM-1 (WISP-1), a WISP-3, a COP-1 (WISP-2), and fragments,
analogs, and derivatives of any of the aforementioned members of
the CCN family of proteins; (b) separately contacting a second
fibroblast cell with a biologically effective amount of an ECM
signaling molecule-related biomaterial described above, thereby
providing a control; (c) measuring the level of cell proliferation
resulting from step (a) and from step (b); and (d) comparing the
levels of cell proliferation measured in step (c), whereby a
modulator of cell proliferation is identified by its ability to
alter the level of cell proliferation when compared to the control
of step (b). Preferred embodiments of the methods of screening for
modulators of cell proliferation involve the use of fibroblasts
presenting an .alpha..sub.6.beta..sub.1 integrin and/or a sulfated
proteoglycan.
[0042] A related aspect of the invention is a modulator of an ECM
signaling molecule identified using the screening methods of the
invention. In one embodiment, Cyr61 is the ECM signaling molecule
whose activity is modulated, induction of angiogenesis and/or cell
adhesion is the activity that is modulated, and the modulator is a
peptide. A preferred peptide modulator of Cyr61-induced
angiogenesis and/or cell adhesion is a peptide having a sequence
derived from domain III of Cyr61, including peptides having the
sequence H.sub.2N--G QKCIVQTTSWSQCSKS--CO.sub.2H and peptides
having amino acid sequences of 80%, 90%, 95% and preferably, 99%
sequence similarity. The peptide modulators of the invention
include ECM signaling molecule fragments of varying length,
variants thereof preferably exhibiting conservative amino acid
substitutions, additions or deletions, and derivatives thereof,
including, but not limited to, peptides that are glycosylated,
PEGylated, phosphorylated, and attached or fused to other peptides
or non-peptide carrier molecules.
[0043] Also comprehended by the invention is a method for expanding
a population of undifferentiated hematopoletic stem cells in
culture, comprising the steps of: (a) obtaining hematopoietic stem
cells from a donor; and (b) culturing said cells under suitable
nutrient conditions in the presence of a biologically effective
(i.e., hematopoietically effective) amount of a Cyr61
polypeptide.
[0044] Another method according to the invention is a method of
screening for a mitogen comprising the steps of: (a) plating cells
capable of undergoing cell proliferation; (b) contacting a first
portion of the cells with a solution comprising Cyr61 and a
suspected mitogen; (c) contacting a second portion of the cells
with a solution comprising Cyr61, thereby providing a control; (c)
incubating the cells; (d) detecting the growth of the first portion
of cells and the second portion of the cells; and (e) comparing
growth of the first and second portions of cells, whereby a mitogen
is identified by its ability to induce greater growth in the first
portion of cells when compared to the growth of the second portion
of cells. The cells include, but are not limited to, endothelial
cells and fibroblast cells. Further, the method may involve
contacting the cells with a nucleic acid label, e.g.,
[.sup.3H]-thymidine, and detecting the presence of the label in the
cells. Another method relates to improving tissue grafting,
comprising administering to an animal a quantity of Cyr61 effective
in improving the rate of neovascularization of a graft.
[0045] In other aspects, the invention is drawn to a method of
screening for a modulator of binding between a Cyr61 polypeptide
and a Cyr61 receptor integrin selected from the group consisting of
.alpha..sub.V.beta..sub.3, .alpha..sub.V.beta..sub.5,
.alpha..sub.6.beta..sub.1, .alpha..sub.11.beta..sub.3 and
.alpha..sub.M.beta..sub.2, comprising the steps of: a) contacting a
Cyr61 polypeptide with an integrin receptor composition in the
presence and in the absence of a potential modulator compound; b)
detecting binding between the polypeptide and the integrin
receptor; and c) identifying a modulator compound in view of
decreased or increased binding between the Cyr61 polypeptide and
the integrin receptor in the presence of the modulator, as compared
to binding in the absence of the modulator. Suitable Cyr61
polypeptides include human Cyr61, and fragments, analogs and
derivative thereof. For example, a preferred Cyr61 fragment would
have at least 95% amino acid similarity to residues 1-281 of SEQ ID
NO:4, thereby containing domains I-III, but not domain IV, of
Cyr61. Purified modulators identified by the above-described method
of screening for a modulator of binding between a Cyr61 polypeptide
and a particular integrin receptor are also embraced by the
invention. Further, the invention contemplates the use of a
modulator of a Cyr61-integrin .alpha..sub.V.beta..sub.3 interaction
for preparation of a medicament for the treatment of a condition
selected from the group consisting of atherosclerosis, heart
disease, tumor growth, tumor metastasis, fibrosis, disorders
associated with inadequate angiogenesis, disorders associated with
aberrant granulation tissue development, aberrant fibroblast growth
and wounds.
[0046] In still another aspect, the invention provides a method for
treating a condition characterized by defective connective tissue
in a mammalian subject, comprising the steps of: (a) identifying a
mammalian subject in need of treatment for the condition, and (b)
administering to the mammalian subject a composition comprising a
modulator of an interaction between Cyr61 and an integrin receptor
selected from the group consisting of .alpha..sub.V.beta..sub.3,
.alpha..sub.V.beta..sub.5, .alpha..sub.6.beta..sub.1,
.alpha..sub.11.beta..sub.3 and .alpha..sub.M.beta..sub.2, in an
amount effective to mitigate the symptoms of the condition in the
mammalian subject. Suitable modulators include, but are not limited
to, a modulator selected from the group consisting of heparin,
heparan sulfate and a polypeptide that binds an integrin receptor.
The modulator may be administered in a wide variety of ways,
including the situation where administering is accomplished by
expressing an exogenous polypeptide coding region in cells of the
type affected by said condition. An exemplary polypeptide is a
fragment of a Cyr61 polypeptide, for example a fragment comprising
a sequence selected from the group consisting of residues 280-290
of SEQ ID NO:4 and residues 306-312 of SEQ ID NO:4. Further, a
variety of conditions or disorders (e.g., diseases) and integrin
receptors are contemplated, such as a condition that involves a
defect in fibroblast adhesion and the integrin receptor is
.alpha..sub.6.beta..sub.1, a condition that involves a defect in
fibroblast chemotaxis and the integrin receptor is
.alpha..sub.V.beta..sub.5, and a condition that involves a defect
in fibroblast proliferation and the integrin receptor is
.alpha..sub.V.beta..sub.3.
[0047] Another aspect of the invention is drawn to methods of
treating conditions or disorders, such as diseases, associated with
gene under- or over-expression by delivering a therapeutically
effective amount of an ECM Signaling Molecule (e.g., a Cyr61
polypeptide, Fisp12, CTGF), or a biologically active fragment
thereof, or modulator of a Cyr61-integrin receptor interaction,
using delivery means known in the art. A related aspect of the
invention is drawn to a method for modulating gene expression
comprising the step of administening a biologically effective
amount of a human Cyr61 fragment to a cell capable of Cyr61
-modulated gene expression.
[0048] In yet another aspect, the invention is drawn to a method
for treating a condition characterized by a defect in smooth muscle
tissue in a mammalian subject, comprising the steps of: (a)
identifying a mammalian subject in need of treatment for the
condition, and (b) administering to the mammalian subject a
composition comprising a modulator of an interaction between Cyr61
and an .alpha..sub.6.beta..sub.1 integrin receptor in an amount
effective to mitigate the symptoms of the condition in the
mammalian subject. An exemplary modulator is selected from the
group consisting of heparin, heparan sulfate and a polypeptide that
binds an .alpha..sub.6.beta..sub.1 integrin receptor. One of many
suitable means of administering the composition is accomplished by
expressing an exogenous polypeptide coding region in cells of the
type affected by said condition. Again, exemplary Cyr61
polypeptides include fragments of Cyr61, such as a fragment that
comprises at sequence selected from the group consisting of
residues 280-290 of SEQ ID NO:4 and residues 306-312 of SEQ ID
NO:4. Conditions that may be treated by the method include a
condition selected from the group consisting of atherosclerosis,
heart disease, tumor growth, tumor metastasis, fibrosis, disorders
associated with inadequate angiogenesis, disorders associated with
aberrant granulation tissue development, aberrant fibroblast growth
and wounds.
[0049] Another aspect of the invention is directed to a kit for
assaying for Cyr61-integrin receptor interactions, the kit
comprising a Cyr61 polypeptide and a composition comprising an
integrin receptor selected from the group consisting of
.alpha..sub.V.beta..sub.3, .alpha..sub.V.beta..sub.5,
.alpha..sub.6.beta..sub.1, .alpha..sub.11.beta..sub.3 and
.alpha..sub.M.beta..sub.2. An exemplary kit contains an integrin
receptor composition that comprises an .alpha..sub.V.beta..sub.3
integrin localized in a mammalian fibroblast cell membrane.
[0050] Numerous additional aspects and advantages of the present
invention will be apparent upon consideration of the following
drawing and detailed description.
BRIEF DESCRIPTION OF THE DRAWING
[0051] FIG. 1 presents the comparative amino acid sequences of
members of the cysteine-rich protein family of growth-regulating
proteins.
DETAILED DESCRIPTION OF THE INVENTION
[0052] In the mouse, the Cyr61 protein has been found to influence
cell adhesion, migration, and proliferation. The cyr61 gene, which
encodes Cyr61, is an immediate-early gene that is transcriptionally
activated by serum growth factors in mouse fibroblasts. Lau et al.,
EMBO J. 4:3145-3151 (1985), incorporated herein by reference; Lau
et al., Proc. Natl. Acad. Sci. (USA) 84:1182-1186 (1987),
incorporated herein by reference. The murine cyr61 cDNA coding
sequence is set forth in SEQ ID NO:1. (The human cyr61 cDNA coding
sequence is provided in SEQ ID NO:3). The amino acid sequence of
murine Cyr61 is set out in SEQ ID NO:2. (The human Cyr61 amino acid
sequence is presented in SEQ ID NO:4). Cyr61 is a 41 kDa
polypeptide exhibiting 39 cysteine residues, approximately 10% of
the 379 amino acids constituting the unprocessed protein. Yang et
al., Cell Growth & Diff. 2:351-357 (1991), incorporated herein
by reference. Investigations have revealed that murine Cyr61 binds
heparin and is secreted. Yang et al. Consistent with the observed
secretion of Cyr61 is the identification of an N-terminal signal
sequence in nascent Cyr61, deduced from inspection of the murine
cyr61 cDNA sequence. Yang et al. Additionally, Cyr61 is not found
in the conditioned medium of cultured cells expressing cyr61, but
is found associated with the extracellular matrix (ECM) and the
cell surface. Yang et al. Structurally similar cysteine-rich
mammalian proteins have been characterized.
[0053] Fisp12, a cysteine-rich murine protein, exhibits structural
similarity to Cyr61. The cDNA sequence encoding Fisp12 is set forth
in SEQ ID NO:5; the amino acid sequence of Fisp12 is presented in
SEQ ID NO:6. Murine Fisp12, like Cyr61, influences cell adhesion,
proliferation and migration. The human ortholog of Fisp12 is
Connective Tissue Growth Factor (CTGF), a protein similar in
structure and function to Cyr61. Fisp 12, and CTGF, are
distinguishable from Cyr61, however. For example, a greater
proportion of secreted Fisp12 is found in the culture medium than
is the case with Cyr61; a correspondingly lower proportion of
Fisp12 is localized in the area of expressing cells (cell surface
and nearby extracellular matrix) than is found with Cyr61.
Additional similarities and distinctions among the proteins
comprising the ECM signaling molecules of the invention will become
apparent in the recitations below.
[0054] The present invention has multiple aspects, illustrated by
the following examples. Example 1 describes the cloning of
polynucleotides encoding members of the cysteine-rich protein
family of ECM signaling molecules; Example 2 describes sequence
analyses; Example 3 describes RNA analyses; Example 4 describes the
production of transgenic animals; Example 5 describes the
expression of Cyr61 polypeptides; Example 6 describes the
expression of Fisp12 polypeptides; Example 7 sets out methods of
polypeptide purification; Example 8 provides a characterization of
the polypeptides of the invention; Example 9 discloses a heparin
binding assay for the polypeptide members of the cysteine-rich
protein family; Example 10 is directed to receptors for the
polypeptides; Example 11 describes anti-ECM signaling molecule
antibodies; Example 12 is directed to inihibitory peptides; Example
13 describes cell adhesion and polypeptide-based methods for
influencing the process of cell adhesion, Example 14 describes
polypeptide-influenced migration of fibroblasts; Example 15
describes the migration of endothelial cells and in vitro assays
for migration; Example 16 describes an in vitro assay for
inhibitors of endothelial cell migration; Example 17 describes an
in vivo assay for endothelial cell migration; Example 18 describes
mitogen potentiation by the polypeptides of the invention; Example
19 describes an in vivo cornea assay for angiogenic factors and
modulators; Example 20 is directed to methods for influencing blood
clotting using the polypeptides of the invention; Example 21
discloses the use of the polypeptides for ex vivo hematopoietic
stem cell cultures; Example 22 addresses organ regeneration;
Example 23 describes chondrogenesis and the expression of
extracellular matrix signaling molecules in mesenchyme cells;
Example 24 describes the promotion of cell adhesion in the process
of chondrogenesis using the polypeptides of the invention; Example
25 describes chondrogenesis and the influence of the polypeptides
of the invention on cell aggregation; Example 26 describes the
promotion of cell proliferation by polypeptides of the invention in
the process of chondrogenesis; Example 27 addresses methods for
using the polypeptides of the invention to affect chondrogenesis;
Example 28 provides genetic approaches to the use of
polynucleotides of the invention; Example 29 describes Fibroblast
adhesion, Example 30 addresses angiogenesis, Example 31 relates to
insertional inactivation or knock-out genetic constructs, Example
32 describes adhesion to platelets and macrophages, and Example 33
describes peptide modulators of Cyr61 activity. These examples are
intended to be illustrative of the present invention and should not
be construed to limit the scope of the invention.
EXAMPLE 1
Polynucleotide Cloning
[0055] Initially, an attempt was made to isolate a human cyr61 cDNA
from a human placental cDNA library by probing with the murine
cyr61 cDNA sequence using techniques that are standard in the art.
See Sambrook et al., incorporated herein by reference. Isolation of
the complete murine cyr61 cDNA from a BALB/c 373 (ATCC CRL-1658)
cDNA library has been described. O'Brien et al., Mol. Cell. Biol.
10:3569-3577 (1990), incorporated herein by reference. The
nucleotide and deduced amino acid sequences of murine cyr61 are
available from the Genbank database under accession number M32490.
The nucleotide sequence of murine cyr61 is presented in SEQ ID
NO:1; the murine Cyr61 amino acid sequence is presented in SEQ ID
NO:2.
[0056] The human cDNA library was constructed using .lambda.gt11
(Promega Corp., Madison, Wis.) as a vector which was transfected
into E. coli and plated on LB agar. A murine cDNA expression
construct cloned in pGEM-2 (O'Brien et al., [1990]), containing the
entire murine cyr61 coding sequence [nucleotides 56-1560, using the
numbering of O'Brien et al., (1990); see SEQ ID NO:1] was used as a
probe. The mouse cDNA probe was radiolabeled by techniques standard
in the art. Sambrook et al. Plaque screenings using the mouse probe
were performed using standard techniques. Sambrook et al.
[0057] More particularly, agar plates containing the human cDNA
library described above were exposed to nitrocellulose filters
(BA85, 82 mm, Schleicher & Schuell, Keene, N.H.) were placed on
each plate. After plaque adsorption (approximately 20 minutes), the
filters were removed and air dried for approximately 30 minutes.
Subsequently, each filter was sequentially submerged for 30-60
seconds in 0.2 M NaOH, 1.5 M NaCl (100 ml); 2.times. SSC, 0.4 M
Tris-HCl, pH 7.4 (100 ml); and 0.2.times. SSC (100 ml). Filters
were then dried at room temperature for approximately 1 hour and
subjected to 80.degree. C. under vacuum for 2 hours. Filters were
probed with radiolabeled murine cyr61 cDNA. The excessive number of
signals, indicative of a high level of false positive signals from
related sequences, prevented identification of cyr61 cDNA.
[0058] Turning to a complicated, cyr61-specific cloning strategy,
human cyr61 cDNA clones were identified with probes generated by
RT-PCR. In particular, the probe for screening the human placental
cDNA library was a PCR fragment generated with degenerate primers
by RT-PCR of total RNA from logarithmically growing WI38 cells. The
primers were derived from the sequences corresponding to the most
conserved region of the open reading frame of the mouse cyr61 cDNA.
One primer, designated H61-5
[5'-GGGAATTCTG(TC)GG(GATC)TG(TC)TG(TC)AA(GA)GT(GC)TG-3'], contains
a degenerate sequence which, with the exception of the "GGGAATTC"
sequence at the 5' end which was used to introduce an EcoRI site,
is derived from nuclcotides 327-346 (sense strand) of the mouse
cyr61 sequence set forth in SEQ ID NO:1. The degeneracies appear in
positions corresponding to the third position of codons in SEQ ID
NO:1. The second primer used for PCR amplification of a human cyr61
sequence was designated H61-3
[5'-CCGGATCC(GA)CA(GA)TT(GA)TA(GA)TT(GA)CA-3'], which, with the
exception of the 5' sequence "CCGGATCC" used to introduce a BamHI
site, corresponds to the anti-sense strand complementary to
nucleotides 1236-1250 of the mouse cyr61 sequence set forth in SEQ
ID NO:1. The degeneracies occur in positions complementary to the
third positions of codons in mouse cyr61 as set forth in SEQ ID
NO:1. The amplified cyr61 cDNA was cloned into the pBlueScript SK+
vector (Stratagene, La Jolla, Calif.) and sequenced with a
Sequenase II kit (U.S. Biochemicals, Cleveland, Ohio).
[0059] Serial screenings of the human placental cDNA library led to
the isolation of a clone containing a human cyr61 cDNA. The human
cyr61 cDNA is approximately 1,500 bp in length. The human cDNA is
contained on an EcoRI fragment cloned into the EcoRI site in
pGEM-2. As shown in SEQ ID NO:3, the human cDNA sequence includes
the entire coding region for human Cyr61, along with 120 bp of 5'
flanking sequence, and about 150 bp of 3' flanking sequence.
[0060] The polynucleotides of the invention may be wholly or
partially synthetic, DNA or RNA, and single- or double-stranded.
Because polynucleotides of the invention encode ECM signaling
molecule polypeptides which may be fragments of an ECM signaling
molecule protein, the polynucleotides may encode a partial sequence
of an ECM signaling molecule. Polynucleotide sequences of the
invention are useful for the production of ECM signaling molecules
by recombinant methods and as hybridization probes for
polynucleotides encoding ECM signaling molecules.
[0061] DNA polynucleotides according to the invention include
genomic DNAs, cDNAs, and oligonucleotides comprising a coding
sequence of an ECM signaling molecule, or a fragment or analog of
an ECM signaling molecule, as described above, that retains at
least one of the biological activities of an ECM signaling molecule
such as the ability to promote cell adhesion, cell migration, or
cell proliferation in such biological processes as angiogenesis,
chondrogenesis, and oncogenesis, or the ability to elicit an
antibody recognizing an ECM signaling molecule.
[0062] Other polynucleotides according to the invention differ in
sequence from sequences contained within native ECM signaling
molecule polynucleotides (i.e., by the addition, deletion,
insertion, or substitution of nucleotides) provided the
polynucleotides encode a protein that retains at least one of the
biological activities of an ECM signaling molecule. A
polynucleotide sequence of the invention may differ from a native
ECM signaling molecule polynucleotide sequence by silent mutations
that do not alter the sequence of amino acids encoded therein.
Additionally, polynucleotides of the invention may specify an ECM
signaling molecule that differs in amino acid sequence from native
ECM signaling molecule sequences or subsequences, as described
above. For example, polynucleotides encoding polypeptides that
differ in amino acid sequence from native ECM signaling molecules
by conservative replacement of one or more amino acid residues, are
contemplated by the invention. The invention also extends to
polynucleotides that hybridize under standard stringent conditions
to polynucleotides encoding an ECM signaling molecule of the
invention, or that would hybridize but for the degeneracy of the
genetic code. Exemplary stringent hybridization conditions involve
hybridization at 42.degree. C. in 50% formamide, 5.times. SSC, 20
mM Na.multidot.PO.sub.4, pH 6.8 and washing in 0.2.times. SSC at
55.degree. C. It is understood by those of skill in the art that
variation in these conditions occurs based on the length and GC
nucleotide content of the sequences to be hybridized. Formulas
standard in the art are appropriate for determining exact
hybridization conditions. See Sambrook et al. Molecular Cloning: A
Laboratory Manual (Second ed., Cold Spring Harbor Laboratory Press
1989) .sctn..sctn. 9.47-9.51.
[0063] ECM signaling molecule polynucleotides comprising RNA are
also within the scope of the present invention. A preferred RNA
polynucleotide according to the invention is an mRNA of human
cyr61. Other RNA polynucleotides of the invention include RNAs that
differ from a native ECM signaling molecule mRNA by the insertion,
deletion, addition, or substitution of nucleotides (see above),
with the proviso that they encode a polypeptide retaining a
biological activity associated with an ECM signaling molecule.
Still other RNAs of the invention include anti-sense RNAs (i.e.,
RNAs comprising an RNA sequence that is complementary to an ECM
signaling molecule mRNA).
[0064] Accordingly, in another embodiment a set of DNA fragments
collectively spanning the human cyr61 cDNA were cloned in pGEM-2
and M13 derivatives using methods well known in the art to
facilitate nucleotide sequence analyses. The pGEM-2 clones provided
substrates for the enzymatic generation of serial deletions using
techniques known in the art. This collection of clones,
collectively containing a series of DNA fragments spanning various
parts of the cyr61 cDNA coding region, are useful in the methods of
the invention. The resulting series of nested pGEM-2 clones, in
turn, provided substrates for nucleotide sequence analyses using
the enzymatic chain terminating technique. The fragments are also
useful as nucleic acid probes and for preparing Cyr61 deletion or
truncation analogs. For example, the cyr61 cDNA clones may be used
to isolate cyr61 clones from human genomic libraries that are
commercially available. (Clontech Laboratories, Inc., Palo Alto,
Calif.). Genomic clones, in turn, may be used to map the cyr61
locus in the human genome, a locus that may be associated with a
known disease locus.
[0065] Other embodiments involve the polynucleotides of the
invention contained in a variety of vectors, including plasmid,
viral (e.g., prokaryotic and eukaryotic viral vectors derived from
Lambda phage, Herpesviruses, Adenovirus, Adeno-associated viruses,
Cytomegalovirus, Vaccinia Virus, the M13-f1-fd family of viruses,
retroviruses, Baculovirus, and others), phagemid, cosmid, and YAC
(i.e., Yeast Artificial Chromosome) vectors.
[0066] Yet other embodiments involve the polynucleotides of the
invention contained within heterologous polynucleotide
environments. Polynucleotides of the invention have been inserted
into heterologous genomes, thereby creating transgenes, and
transgenic animals, according to the invention. In particular, two
types of gene fusions containing partial murine cry61 gene
sequences have been used to generate transgenic mice. (See below).
One tyne of fused gene recombined the coding sequence of cyr61 with
one of three different promoters: 1) the K14 keratin promoter, 2)
the .beta.-actin promoter, or 3) the phosphoglycerokinase promoter.
Adra et al., Gene 60:65-74 (1987). These fusion constructs were
generated using standard techniques, as described below in the
context of a phosphoglycerokinase promoter (pgk-1)-cyr61 fusion. An
XhoI-Sca1 genomic DNA fragment containing the entire cyr61 coding
region and all introns, but lacking the transcription initiation
site and polyadenylation signal, was cloned into plasmid
pgk/.beta.-gal, replacing the lacZ coding sequence. The resulting
construct placed cyr61 under the control of the strong pgk-1
promoter which is active in all cells.
[0067] The second type of gene fusion recombined the cyr61
expression control sequences (i.e., promoter) with the E. coli
.beta.-galactosidase coding sequence. The cyr61-lacZ fusion gene
was constructed using the following approach. A DNA fragment
spanning nucleotides -2065 to +65 relative to the transcription
initiation nucleotide was used to replace the pgk-1 promoter (Adra
et al. [1987]) in plasmid pgk/.beta.-gal by blunt-end cloning. In
addition, the polyadenylation signal from the bovine growth honnone
gene was cloned into the plasmid containing the fusion gene. The
resulting construct, plasmid 2/lacZ, has the E. coli lacZ gene
under the transcriptional control of a 2 kb DNA fragment containing
the cyr61 promoter. The related plasmid 1.4/lacZ was derived from
plasmid 2lacZ by removing about 600 bp of cyr61 DNA found upstream
of an AflII site. Also, plasmid 2M/lacZ resembles plasmid 2/lacZ,
except for a C-to-T transition in the CArG Box, created by PCR.
These constructs were excised from the vectors by NotI digestion,
purified using GeneClean (Bio101, Inc., La Jolla, Calif.), and used
to generate transgenic mice (see below).
[0068] A cDNA fragment encoding mouse fisp12 has also been cloned
using standard techniques. Ryseck et al., Cell Growth & Diff.
2:225-233 (1991), incorporated herein by reference. The cloning was
accomplished by ligating an Xholl fragment containing the fisp12
cDNA coding region into BamHI-cleaved pBlueBacIII, a baculovirus
expression vector (Invitrogen Corp., San Diego, Calif.).
Recombinant baculovirus clones were obtained as described in
Summers et al., TX Ag. Exp. Sta., Bulletin 1555 (1987).
[0069] The human ortholog of fisp12, the gene encoding CTGF, was
cloned by screening a fusion cDNA library with
anti-Platelet-Derived Growth Factor (anti-PDGF) antibodies, as
described in U.S. Pat. No. 5,408,040, column 12, line 16, to column
13, line 29, incorporated herein by reference. The screening
strategy exploited the immunological cross-reactivity of CTGF and
PDGF.
[0070] The cloned copies of the cyr61, fisp12, and ctgf cDNAs
provide a ready source for polynucleotide probes to facilitate the
isolation of genomic coding regions, as well as allelic variants of
the genomic DNAs or cDNAs. In addition, the existing cDNA clones,
or clones isolated by probing as described above, may be used to
generate transgenic organisms. For example, transgenic mice
harboring cyr61 have been generated using standard techniques, as
described in the next Example.
[0071] A clone, hCyr61 cDNA, containing the human cyr61 cDNA
sequence set forth in SEQ ID NO:3, and a bacterial strain
transformed with that clone, Escherichia coli DH5.alpha.
(hCyr61cDNA), were deposited with the American Type Culture
Collection, 10801 University Blvd., Manassas, Va. 20110-2209 USA
(formerly at 12301 Parklawn Drive, Rockville, Md. 20852 USA), on
Mar. 14, 1997.
EXAMPLE 2
Sequence Analyses
[0072] The nucleotide sequence of murine cyr61 has been described,
O'Brien et al. (1990); Latinkic et al. Nucl. Acids Res.
19:3261-3267 (1991), and is set out herein as SEQ ID NO:1.
[0073] The deduced amino acid sequence of murine Cyr61 has been
reported, O'Brien et al. (1990), and is set forth in SEQ ID
NO:2.
[0074] The nucleotide sequence of the human cyr61 cDNA was
determined using the method of Sanger, as described in Sambrook et
al. Sequencing templates were generated by constructing a series of
nested deletions from a pGEM-2 human cyr61 cDNA clone, as described
in Example 1 above. The human cyr61 cDNA sequence is set forth in
SEQ ID NO:3. The amino acid sequence of human Cyr61 was deduced
from the human cyr61 cDNA sequence and is set forth in SEQ ID
NO:4.
[0075] A comparison of the mouse and human Cyr61 sequences,
presented in SEQ ID NO:2 and SEQ ID NO:4, respectively, reveals 91%
similarity. Both sequences exhibit an N-terminal signal sequence
indicative of a processed and secreted protein; both proteins also
contain 38 cysteine residues, distributed throughout both proteins
but notably absent from the central regions of both murine and
human Cyr61. Notably, the region of greatest sequence divergence
between the mouse and human Cyr61 coding regions is this central
region free of cysteine residues. However, the 5' untranslated
regions of the mouse and human cyr61 cDNAs are even more divergent
(67% similarity). In contrast, the 3' untranslated regions are the
most similar regions (91% similarity). In overall length, the
encoded murine Cyr61 has 379 amino acids; human Cyr61 has 381 amino
acids.
[0076] A fisp12 cDNA sequence has also been determined and is set
out in SEQ ID NO:5. The amino acid sequence of Fisp12 has been
deduced from the fisp12 cDNA sequence and is set forth in SEQ ID
NO:6. A comparison of the amino acid sequences of murine Cyr61 and
Fisp12 reveals that the two proteins are 65% identical. The
structural similarity of Cyr61 and Fisp12 is consistent with the
similar functional properties of the two proteins, described
below.
[0077] A partial cDNA sequence of CTGF, containing the complete
CTGF coding region, has also been determined. The CTGF cDNA
sequence was obtained using M13 clones as templates for enzymatic
sequencing reactions, as described. '040 Patent, at column 12, line
68 to column 13, line 14. Additional cloning coupled with
double-stranded enzymatic sequencing reactions, elucidated the
entire sequence of the cDNA encoding CTGF. U.S. Pat. No. 5,408,040,
column 14, line 44, to column 15, line 8, incorporated herein by
reference. The nucleotide sequence of the cDNA encoding CTGF is
presented herein in SEQ ID NO:7. The deduced amino acid sequence of
the cDNA encoding CTGF is presented in SEQ ID NO:8.
EXAMPLE 3
RNA Analyses
[0078] Polynucleotide probes are useful diagnostic tools for
angiogenic, and other, disorders correlated with Cyr61 expression
because properly designed probes can reveal the location, and
level, of cyr61 gene expression at the transcriptional level. The
expression of cyr61, in turn, indicates whether or not genes
controlling the process of angiogenesis are being expressed at
typical, or expected, levels.
[0079] Using these tools, the mouse cyr61 mRNA expression pattern
was determined using an RNase protection technique. O'Brien et al.,
(1992). In particular, a 289 nucleotide antisense riboprobe was
used that would protect 246 nucleotides of the murine cyr61 mRNA
(nucleotides 67 to 313 using the numbering of O'Brien et al.) The
assays showed levels of cyr61 mRNA in PSA-1 cells (10 .mu.g of
total RNA) from either the undifferentiated state or stages 1, 2,
and 3 of differentiation (PSA-1 cells undergo three stages of
cellular differentiation corresponding to mouse embryonic cells of
the following gestational ages, in days: 4.5-6.5 [PSA-1 stage 1];
6.5-8.5 [PSA-1 stage 2]; 8.5-10.5 [PSA-1 stage 3]). A comparison of
the protection of whole embryonic and placental total RNAs (20
.mu.g each) showed that cyr61 is expressed in embryonic tissues at
times that are coincident with the processes of cell
differentiation and proliferation.
[0080] Expression characteristics of human cyr61 were determined by
Northern analyses, using techniques that are standard in the art.
Sambrook et al. RNA was isolated from the human diploid
fibroblastic cell line WI38 (ATCC CCL-75). In addition, RNA was
isolated from rat cells (REF52), hamster cells (CHO), and monkey
cells (BSC40). Each of the cell lines was grown to confluence in
MEM-10 (Eagle's Minimal Essential Medium with Earle's salts
[GIBCO-BRL, Inc.], 2 mM glutamine, and 10% fetal calf serum [fcs])
and maintained in MEM-0.5 (a 0.5% serum medium) for two days.
Cultures were then stimulated with 20% fcs, in the presence or
absence of cycloheximide, by techniques known in the art. Lau et
al. (1985; 1987). Ten microgram aliquots of RNA isolated from these
cell lines were then fractionated by formaldehyde-agarose gel
electrophoresis, transferred and immobilized on nitrocellulose
filters, and exposed to a full-length [.sup.32P]-radiolabeled
murine cyr61 cDNA probe under hybridization conditions of high
stringency. Human cyr61 RNA expression was similar to murine cyr61
expression. Both mouse and human cyr61 expression yielded
approximately 2 kilobase RNAs. Additionally, both mouse and human
expression of Cyr61 were stimulated by serum and were resistant to
cycloheximide.
[0081] The distribution of human cyr61 mRNA was also examined using
multiple tissue Northem blots (Clontech). The blots were hybridized
in an ExpressHyb Solution (Clontech) according to the
manufacturer's instructions. The results showed that cyr61 mRNA is
abundant in the human heart, lung, pancreas, and placenta; is
present at low levels in skeletal muscle, kidney and brain; and is
not detectable in liver. These results are consistent with the
expression of cyr61 in mouse tissues.
[0082] In addition, total cellular RNA was isolated from human skin
fibroblasts (HSFs) that were either quiescent, growing
exponentially, stimulated by serum, or exposed to cycloheximide.
HUVE cells (ATCC CRL 1730) were maintained in Ham's F12 medium
supplemented with 10% fbs (Intergene), 100 .mu.g/ml heparin (Gibco
BRL) and 30 .mu.g/ml endothelial cell growth supplement
(Collaborative Biomedical Products). Human skin fibroblasts (HSF,
ATCC CRL-1475) and WI38 fibroblasts (ATCC CCL-75) were grown in
Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10%
fbs. Quiescent HSFs were prepared by growth in DMEM supplemented
with 10% fbs to confluence followed by changing the medium to DMEM
containing 0.1% fbs, for 2 days. Serum stimulation was carried out
by changing the medium to 20% fbs for 1 hour. Where indicated,
cycloheximide was added to 10 .mu.g/ml simultaneously with serum
for 3 hours.
[0083] RNAs from the aforementioned cells were isolated using a
guanidinium isothiocyanate protocol. Chomczynski et al., Anal.
Biochem. 162:156-159(1987). RNA samples were analyzed by
electrophoretic separation in formaldehyde-agarose gels followed by
transfer to nylon filters. Blots were hybridized with random-primed
probes generated using either cyr61 or GAPDH as a template. Adams
et al., Nature 355:632-634 (1992). The results indicated that human
cyr61 mRNA is not detectably present in quiescent human skin
fibroblasts, is abundant in logarithmically growing and serum
stimulated HSFs, and is superinduced by cycloheximide.
[0084] The analysis of RNA encoding CTGF also involved techniques
that are standard in the art. In particular, investigation of RNA
encoding CTGF involved the isolation of total cellular RNA and
Northern analyses, performed as described in U.S. Pat. No.
5,408,040, column 11, line 59, to column 12, line 14, and column
13, lines 10-29, incorporated herein by reference. A 2.4 kb RNA was
identified. The expression of CTGF was high in the placenta, lung,
heart, kidney, skeletal muscle and pancreas. However, CTGF
expression was low in the liver and brain.
EXAMPLE 4
Transgenic Animals
[0085] The construction of transgenic mice bearing integrated
copies of recombinant cyr61 sequences was accomplished using linear
DNA fragments containing a fusion gene. The cyr61 coding sequence
was independently fused to the .beta.-actin, K14, and pgk
promoters, described above. Expression of cyr61 was driven by these
promoters in the transgenic animals. The fusion gene was produced
by appropriate restriction endonuclease digestions, using standard
techniques. The fusion gene fragments were injected into
single-cell zygotes of Swiss Webster mice. The injected zygotes
were then implanted into pseudopregnant females. Several litters of
mice were produced in this manner. Newboms exhibiting unusual
phenotypes were subjected to additional analyses. For example,
neonatal transgenic mice expressing cyr61 under the pgk promoter
exhibited skeletal deformities, including curly tails, immobile
joints, and twisted limbs, resulting in locomotive difficulties.
These mice typically were runted and died within seven days of
birth. Transgenic mice expressing cyr61 under the .beta.-actin
promoter showed no obvious phenotype except that the mice were
smaller. When mice bearing the transgene were back-crossed to the
in-bred strain C57BL/6, the progeny mice became progressively more
runted with continued back-crossing. After three to four such
back-crosses, essentially no progeny survive to reproduce.
Transgenic mice expressing cyr61 under the K14 promoter exhibited a
form of fibrotic dermatitis. The pathology involved excessive
surface scratching, sometimes resulting in bleeding. Transgenic
organisms having knockout mutations of cyr61 can also be created
using these standard techniques, Hogan et al., Manipulating the
Mouse Embryo: A Laboratory Manual (Cold Spring Harbor Laboratory
Press 1994), and are useful as models of disease states.
EXAMPLE 5
Cyr61 Expression
[0086] Native Cyr61 is expressed in embryonic tissues and is
induced in a variety of wounded tissues. See below; see also,
O'Brien et al. (1992). The tissue distribution of Cyr61 was
examined with rabbit anti-Cyr61 polyclonal antibodies elicited
using a conventional immunological technique (Harlow et al., 1987)
and affinity-purified. Using affinity-purified anti-Cyr61
polyclonal antibodies according to the invention, cyr61 expression
was found in a variety of tissues, including smooth muscle,
cardiomyocytes, and endothelia of the cardiovascular system; brain,
spinal cord, ganglia and neurons, and retina of the nervous system;
cartilage and bone of the skeletal system; epidermis, hair, oral
epithelia, and cornea of the skin; bronchioles and blood vessels of
the lung; and placental tissues. In addition to expression studies
directed towards native cyr61 (mRNA and protein), studies using
cyr61 transgenes, as described above, have contributed to our
understanding of Cyr61 expression. The use of transgene fusions
comprising the expression control sequences of cyr61 and the coding
sequence of lacZ (encoding .beta.-galactosidase) has provided a
convenient colorimetric assay for protein expression.
[0087] The colorimetric assay involves the use of
5-Bromo-4-Chloro-3-Indol- yl-.beta.-D-Galactopyranoside (i.e.,
X-Gal) as a substrate for .beta.-galactosidase, the gene product of
lacZ. Enzymatic cleavage of X-Gal by .beta.-galactosidase produces
an intensely colored indigo dye useful in histochemical staining.
In practice, embryonic and adult tissues subjected to analysis were
dissected and fixed in 2% formaldehyde, 0.2% glutaraldehyde, 0.02%
Nonidet P-40, and 0.01 sodium deoxycholate, in standard
phosphate-buffered saline (PBS). Fixation times varied from 15-120
minutes, depending on the size and density of organ or embryo
samples being subjected to analysis. Subsequently, samples were
rinsed in PBS and stained overnight at 37.degree. C. in a PBS
solution containing 5 mM potassium ferrocyanide, 5 mM potassium
ferricyanide, 2 mM MgCl.sub.2, 0.02% Nonidet P-40, 0.01% sodium
deoxycholate and 1 mg/ml of X-Gal (40 mg/ml in dimethylsulfoxide
[DMSO]). Samples were then rinsed in PBS, post-fixed in 4%
paraformaldehyde for 1-2 hours, and stored in 70% ethanol at
4.degree. C. until subjected to microscopic examination. Mice
containing the cyr61-lacZ transgene were used to map the expression
profile of cyr61. The results are presented in Table I for
embryonic tissues at day 12.5.
1TABLE I Transgenic Blood Nervous Mouse Line Vessels Skeleton
System Epidermis .sup. 1.S.sup.1 .sup. +.sup.2 - + + 2.S + + + +
3.S + +/- + + 4.T + - - NA 5.T + - - NA 6.T + +/- - NA 7.T + +/- -
NA 8.T + +/- + NA .sup.1Transgenic lines, S- stable (established)
transgenic lines; T- transient lines .sup.2+/- Expression pattern
only partially reproduced.
[0088] The results indicate that Cyr61 is expressed in a variety of
embryonic cell types. Additional information has been gleaned from
the ectopic expression of Cyr61 resulting from another type of
transgene fusion comprising a heterologous expression control
sequence coupled to the coding sequence of cyr61. The control
sequences, the K14 keratin promoter, the .beta.-actin promoter, and
the phosphoglycerokinase promoter, directed the expression of Cyr61
in a pattern that differed from its native expression.
[0089] Transgenic mice ectopically expressing Cyr61 were routinely
smaller than wild type mice and exhibited a reduction in average
life span. Moreover, these transgenic mice had abnormal hearts
(i.e., thickened chamber walls with a corresponding reduction in
internal capacity) and abnormal skeletons characterized by curved
spines, joints swollen to the point of immobility, and curly tails.
Therefore, ectopic expression of Cyr61 interferes with angiogenesis
(blood vessel development and heart development) and chondrogenesis
(skeletal development). In addition, transgenic mice carrying
knockout mutations of cyr61 may be developed and tested as models
of disease states associated with a lack of Cyr61 activity.
[0090] A strategy for the expression of recombinant cyr61 was
designed using a Baculovirus expression vector in Sf9 cells.
Expression systems involving Baculovirus expression vectors and Sf9
cells are described in Current Protocols in Molecular Biology
.sctn..sctn. 16.9.1-16.12.6 (Ausubel et al., eds., 1987). One
embodiment of the present invention implemented the expression
strategy by cloning the murine cyr61 cDNA into pBlueBac2, a
transfer vector. The recombinant clone, along with target AcMNPV
(i.e., Autographa californica nuclear polyhedrosis virus, or
Baculovirus) DNA, were delivered into Sf9 cells by
liposome-mediated transfection, using the MaxBac Kit (Invitrogen,
Inc., San Diego, Calif.) according to the manufacturer's
instructions. Recombinant virus was plaque-purified and amplified
by 3 passages through Sf9 cells via infection.
[0091] Conditioned medium of Sf9 insect cells infected with a
baculovirus construct driving the synthesis of murine Cyr61 was
used as a source for purification of Cyr61 (see below). The
purified recombinant Cyr61 retains certain characteristics of the
endogenous protein, e.g.. the heparin-binding activity of Cyr61
(described below) from 3T3 fibroblast cells and had a structure
similar to the endogenous protein as revealed by independent
peptide profiles produced by partial proteolysis using either
chymotrypsin or trypsin (sequencing grade; Boehringer-Mannheim,
Inc., Indianapolis, Ind.).
[0092] Human cyr61 was also expressed using the baculovirus system.
A SmaI-HindIlI fragment (corresponding to nucleotides 100-1649 of
SEQ ID NO:3) of cyr61 cDNA spanning the entire human cyr61 open
reading frame was subcloned into a pBlueBac3 baculovirus expression
vector (Invitrogen). Recombinant baculovirtis clones were obtained,
plaque purified and amplified through three passages of Sf9
infection, using conventional techniques. Infection of Sf9 cells
and human Cyr61 (hCyr61) purification was performed using standard
techniques, with some modifications. Sf9 cells were maintained in
serum-free Sf900-II medium (Sigma). Sf9 cells were seeded, at
2-3.times.10.sup.6 cells per 150 mm dish, in monolayer cultures and
were infected with 5 plaque forming units (PFU) of recombinant
virus per cell. The conditioned medium was collected at 8 and 96
hours post-infection, cleared by centrifugation (5000.times. g, 5
minutes) and adjusted to 50 mM MES [2-(N-Morpholino)ethanesulfonic
acid], pH 6.0, 1 mM PMSF (phenylmethylsulfonyl fluoride), and 1 mM
EDTA. The medium was mixed with Sepharose S beads equilibrated with
loading buffer (50 mM MES, pH 6.0, 1 mM PMSF, 1 mM EDTA, 150 mM
NaCl) at a ratio of 5 ml Sepharose S beads per 500 ml of
conditioned medium and the proteins were allowed to bind to the
Sepharose S at 4.degree. C. (o/n) with gentle stirring. Sepharose S
beads were collected by sedimentation without stirring for 20
minutes and applied to the column. The column was washed with 6
volumes of 0.3 M NaCl in loading buffer and recombinant human Cyr61
was eluted from the column with a step gradient of NaCl (0.4-0.8 M)
in loading buffer. This procedure resulted in 3-4 milligrams of
purified Cyr61 protein from 500 ml of conditioned medium, and the
purified Cyr61 was over 90% pure as judged by Coomassie Blue
staining of SDS-gels.
[0093] In another embodiment, the complete human cyr61 cDNA is
cloned into a cytomegalovirus vector such as pBK-CMV (Stratagene,
LaJolla, Calif.) using the Polymerase Chain Reaction (Hayashi, in
PCR: The Polymerase Chain Reaction 3-13 [Mullis et al. eds.,
Birkhauser 1994]) and Taq Polymerase with editing function,
followed by conventional cloning techniques to insert the PCR
fragment into a vector. The expression vector is then introduced
into HUVE cells by liposome-mediated transfection. Recipient clones
containing the vector-borne neo gene are selected using G418.
Selected clones are expanded and Cyr61 expression is identified by
Reverse Transcription-Polymerase Chain Reaction (i.e., RT-PCR;
Chelly et al., in PCR: The Polymerase Chain Reaction 97-109 [Mullis
et al. eds., Birkhauser 1994]) or Enzyme-Linked Immunosorbent
Assays (i.e., ELISA; Stites et al., in Basic and Clinical
Immunology 243 [Stites et al. eds., Appleton & Lange 1991])
assays.
[0094] In other embodiments of the invention, Cyr61 protein is
expressed in bacterial cells or other expression systems (e.g.,
yeast) using the cyr61 cDNA coding region linked to promoters that
are operative in the cell type being used. Using one of these
approaches, Cyr61 protein may be obtained in a form that can be
administered directly to patients, e.g., by intravenous routes, to
treat angiogenic, chondrogenic, or oncogenic disorders. One of
skill in the art would recognize that other administration routes
are also available, e.g., topical or local application,
liposome-mediated delivery techniques, or subcutaneous,
intradermal, intraperitoneal, or intramuscular injection.
EXAMPLE 6
Fisp12 Expression
[0095] The expression of Fisp12, and a comparison of the expression
characteristics of Cyr61 and Fisp12, were investigated using
immunohistochemical techniques. For these immunohistochemical
analyses, tissue samples (see below) were initially subjected to
methyl-Carnoy's fixative (60% methanol, 30% chloroform and 10%
glacial acetic acid) for 2-4 hours. They were then dehydrated,
cleared and infiltrated in Paraplast X-tra wax at 55-56.degree. C.
for minimal duration. 7 .mu.m thick sections were collected on
poly-L-lysine-coated slides (Sigma), mounted and dewaxed. They were
then treated with 0.03% solution of H.sub.2O in methanol for 30
minutes to inactivate endogenous peroxidase activity. After
rehydration, sections were put in Tris-buffered saline (TBS: 10 mM
Tris, pH 7.6 and 140 mM NaCl) for 15 minutes. At that point,
sections were blotted to remove excess TBS with paper towels and
blocked with 3% normal goat serum in TBS for 10 minutes in a humid
chamber. Excess buffer was then drained and primary antibodies
applied. Affinity purified anti-Cyr61 antibodies were diluted 1:50
in 3% normal goat serum-TBS solution. Dilution for
affinity-purified anti-Fisp12 antibody was 1:25. Routine control
was 3% normal goat serum-TBS, or irrelevant antibody (for example,
monoclonal anti-smooth muscle cell .alpha.-actin). Specificity of
staining was confirmed by incubation of anti-Cyr61 or anti-Fisp12
antibodies with an excess of the corresponding antigen on ice for
at least two hours prior to applying to sections. Complete
competition was observed. By contrast, cross-competition
(incubation of anti-Cyr61 antibodies with Fisp12 antigen and vice
versa) did not occur.
[0096] Primary antibodies were left on sections overnight at
4.degree. C. They were then washed with TBS twice, and subjected to
30 minutes incubation with secondary antibodies at room
temperature. Secondary antibodies used were goat anti-rabbit
horseradish peroxidase conjugates from Boehringer-Mannheim, Inc.,
Indianapolis, Ind. (used at 1:400 dilution). Sections were washed
twice in TBS and chromogenic horseradish peroxidase substrate was
applied for 5 minutes (1 mg/ml of diaminobenzidine in 50 mM
Tris-HCl, pH 7.2 and 0.03% H.sub.2O.sub.2). Sections were then
counterstained in Ehrlich's haematoxylin or in Alcian blue,
dehydrated and mounted in Permount.
[0097] Mouse embryos between the neural fold (E8.5, embryo day 8.5)
and late organogenesis (E18.5) stages of development were sectioned
and subjected to immunostaining with antigen-affinity-purified
rabbit anti-Cyr61 and anti-Fisp12 antibodies. As various organs
developed during embryogenesis, the presence of Cyr61 and Fisp12
was determined. Cyr61 and Fisp12 were co-localized in a number of
tissues and organs. A notable example is the placenta, where both
proteins were readily detectable. In particular, both Cyr61 and
Fisp12 were found in and around the trophoblastic giant cells,
corroborating the previous detection of cyr61 mRNA in these cells
by in situ hybridization (O'Brien and Lau, 1992). Both Cyr61 and
Fisp12 signals in immunohistochemical staining were blocked by
either the corresponding Cyr61 or Fisp12 antigen but not by each
other, nor by irrelevant proteins, demonstrating specificity. In
general, Cyr61 and Fisp12 proteins could be detected both
intracellularly and extracellularly.
[0098] In addition to the placenta, both Cyr61 and Fisp12 were
detected in the cardiovascular system, including the smooth muscle,
the cardiomyocytes, and the endothelia. Both proteins were also
found in the bronchioles and the blood vessels in the lung. Low
levels of anti-Cyr61 and anti-Fisp12 staining could be detected
transiently in the skeletal muscle. This staining is associated
with connective tissue sheets, rather than myocytes; in this
instance the staining pattern was clearly extracellular.
[0099] A more complex pattern of distribution was found in the
epidermis and the epithelia. Both Cyr61 and Fisp12 staining could
be detected in the early, single-cell layer of embryonic epidermis,
as well as in later, multilayered differentiating epidermis. Fisp12
in epidermis declined to an undetectable level by the end of
gestation and remained as such through adulthood, whereas Cyr61 was
readily detectable in the epidermis. In the neonate, a strong
staining for Fisp12 was seen in the oral epithelia where Cyr61
staining was much weaker, while Cyr61 was found in the upper
jawbone where Fisp12 was not observed. The anti-Fisp12 signal in
the oral epithelia gradually increased and remained intense into
adulthood. In the tongue, both Cyr61 and Fisp12 were seen in the
keratinized epithelia, although the Fisp12 staining pattern, but
not that of Cyr61, excludes the filiform papillae.
[0100] Aside from the aforementioned sites of localization, Cyr61
and Fisp12 were also uniquely localized in several organ systems.
For example, Cyr61, but not Fisp12, was present in skeletal and
nervous systems. As expected from in situ hybridization results
(O'Brien and Lau, 1992), Cyr61 protein was readily detected in the
sclerotomal masses of the somites, and in cartilage and bone at
later stages of development. In contrast, Fisp12 was not detectable
in the skeletal system. Since correlation with chondrocytic
differentiation is one of the most striking features of cyr61
expression (O'Brien and Lau, 1992), the absence of Fisp12 in the
skeletal system may underscore an important difference in the
biological roles of Cyr61 and Fisp12. In the E14.5 embryo, Cyr61
could be detected in the ventral spinal cord, dorsal ganglia, axial
muscle and sclerotome-derived cartilaginous vertebrae. Fisp12,
however, was not detected in these tissues.
[0101] By contrast, Fisp12 was uniquely present in various
secretory tissues. Beginning at E16.5, Fisp12 could be detected in
the pancreas, kidneys, and salivary glands. In the pancreas, Fisp12
was strictly localized to the periphery of the islets of
Langerhans. In the kidney, strong Fisp12 staining was seen in the
collecting tubules and Henle's loops, regions where Cyr61 was not
found. In the mucous-type submandibular salivary gland only
collecting ducts stained for Fisp12, whereas in the mixed
mucous-serous submandibular gland, both serous acini and collecting
ducts stained. The signal in acini was peripheral, raising the
possibility that Fisp12 is capsule-associated. In simple holocrine
sebaceous glands a strong acellular Fisp12 signal was detected.
[0102] In summary, Cyr61 and Fisp12 have been co-localized in the
placenta, the cardiovascular system, the lung and the skin. Neither
protein was detected in the digestive system or the endocrine
glands. Unique localization of Cyr61 can be detected in the
skeletal and central nervous system, and Fisp12 is found in
secretory tissues where Cyr61 is not.
[0103] An issue closely related to protein expression concerns the
metabolic fate of the expressed proteins. Members of the
cysteine-rich protein family have been localized. As discussed
above, secreted Cyr61 is found in the ECM and on the cell surface
but not in the culture medium (Yang et al., 1991), yet secreted
Fisp12 was readily detected in the culture medium (Ryseck et al.,
1991). To address the question of whether Fisp12 is also
ECM-associated, the fate of both Cyr61 and Fisp12 was followed
using pulse-chase experiments. Seruim-stimulated, sub-confluent NIH
3T3 fibroblasts were metabolically pulse-labeled for 1 hour and
chased in cold medium for various times. Samples were fractionated
into cellular, ECM, and medium fractions followed by
immunoprecipitation to detect Cyr61 and Fisp12. Both proteins have
a similar short half-life of approximately 30 minutes in the
cellular fraction, which incluides both newly synthesized
intracellular proteins as well as secreted proteins associated with
the cell surface (Yang and Lau, 1991). It should be noted that
since Cyr61 is quantitatively secreted after synthesis and only a
minor fraction is stably associated with the ECM, the bulk of
secreted Cyr61 is cell-surface associated (Yang and Lau, 1991).
[0104] A fraction of Cyr61 was chased into the ECM where it
remained stable for several hours. Newly synthesized Fisp12 was
also chased into the ECM, where its half-life was only about 1
hour. A larger fraction of Fisp12 was chased to the conditioned
medium, where no Cyr61 was detectable. Fisp12 in the conditioned
medium also had a short half-life of about 2 hours. Thus, whereas
Cyr61 is strongly associated with the ECM, Fisp12 is associated
with the ECM more transiently. This result suggests that Fisp12
might be able to act at a site distant from its site of synthesis
and secretion, whereas Cyr61 may act more locally.
[0105] Since many ECM proteins associate with the matrix via
interaction with heparan sulfate proteoglycans, the affinity with
which a protein binds heparin might be a factor in its interaction
with the ECM. The results of heparin binding assays, described
below, are consistent with this hypothesis.
EXAMPLE 7
Protein Purification
[0106] Serum-stimulated NIH 3T3 fibroblast cells were lysed to
provide a source of native murine Cyr61. Yang et al. Similarly,
human fibroblasts are a source of native human Cyr61.
[0107] Recombinant murine Cyr61 was purified from Sf9 cells
harboring the recombinant Baculovirus vector, described above,
containing the complete cyr61 coding sequence. Although murine
Cyr61 in Sf9 cell lysates formed insoluble aggregates as was the
case with bacterial cell extracts, approximately 10% of the Cyr61
synthesized was secreted into the medium in a soluble form. The
soluble, secreted form of Cyr61 was therefore subjected to
purification.
[0108] Initially, subconfluent Sf9 cells in monolayer cultures were
generated in supplemented Grace's medium (GIBCO-BRL, Inc., Grand
Island, N.Y.). Grace, Nature 195:788 (1962). The Sf9 cells were
then infected with 10 plaque-forming-units/cell of the recombinant
Baculovirus vector, incubated for 16 hours, and fed with serum-free
Grace's medium. These cells were expanded in serum-free Grace's
Medium. The conditioned medium was collected 48 hours
post-infection, although Cyr61 expression could be detected in the
medium 24 hours after infection. Subsequently, the conditioned
medium was cleared by centrifugation at 5000.times. g for 5
minutes, chilled to 4.degree. C., adjusted to 50 mM MES, pH 6.0, 2
mM EDTA (Ethylenediamine tetraacetic acid), 1 mM PMSF
(Phenylmethylsulfonyl fluoride) and applied to a Sepharose S column
(Sigma Chemical Co., St. Louis, Mo.) at 4.degree. C. (5 ml void
volume per 500 ml medium). The column was washed with a buffer (50
mM MES, pH 6.0. 2 mM EDTA, 0.5 mM PMSF) containing 150 NaCl, and
bound proteins were eluted with a linear gradient of NaCl (0.2-1.0
M) in the same buffer. The pooled fractions of Cyr61 eluted at
0.6-0.7 M NaCl as a distinct broad peak. The column fractions were
90% pure, as determined by 10% SDS-PAGE followed by Coomassie Blue
staining or Western analysis, using techniques that are standard in
the art. Yang et al.; see also, Sambrook et. al., supra. For
Western analysis, blots were probed with affinity-purified
anti-Cyr61 antibodies as described in Yang et al., supra. After
antibody probing, Western blots were stained with ECL.TM. (i.e.,
Enhanced ChemiLuminescence) detection reagents (Amersham Corp.,
Arlington Heights, Ill.). Fractions containing Cyr61 were pooled,
adjusted to pH 7.5 with Tris-HCl, pH 7.5, and glycerol was added to
10% prior to storage of the aliquots at -70.degree. C. Protein
concentration was determined by the modified Lowry method using the
BioRad protein assay kit (BioRad Laboratories, Inc., Hercules,
Calif.). This purification procedure was repeated at least five
times with similar results. The typical yield was 3-4 mg of 90%
pure Cyr61 protein from 500 ml of conditioned medium.
[0109] Fisp12 was purified using a modification of the Cyr61
purification scheme (Kireeva et al., Exp. Cell Res. 233:63-77
[1997]). Serum-free conditioned media (500 ml) of Sf9 cells
infected at 10 pfu per cell were collected 48 hours post-infection
and loaded onto a 5-ml Sepharose S (Sigma Chemical Co., St. Louis,
Mo.) column. After extensive washing at 0.2 M and 0.4 M NaCl, bound
proteins were recovered by step elution with 50 mM MES (pH 6.0)
containing 0.5 M NaCl. Fractions containing Fisp12 of greater than
80% purity were pooled, NaCl adjusted to 0.15 M and the protein was
concentrated 3-5 fold on a 0.5 ml Sepharose S column with elution
of the protein at 0.6 M NaCl.
[0110] This purification scheme allowed the isolation of 1.5 mg of
recombinant Fisp12 protein of at least 80% purity from 500 ml of
serum-free conditioned media.
[0111] CTGF was purified by affinity chromatography using anti-PDGF
cross-reactivity between CTGF and PDGF, as described in U.S. Pat.
No. 5,408,040, column 7, line 15, to column 9, line 63,
incorporated herein by reference.
EXAMPLE 8
Polypeptide Characterization
[0112] The murine Cyr61 protein has a M, of 41,000 and is 379 amino
acids long including the N-terminal secretory signal. There is 91%
amino acid sequence identity with the 381 amino acid sequence of
the human protein. Those regions of the mouse and human proteins
contributing to the similarity of the two proteins would be
expected to participate in the biological activities shared by the
two polypeptides and disclosed herein. However, the mouse and human
proteins do diverge significantly in the central portion of the
proteins, where each protein is devoid of cysteines. See, O'Brien
et al., Cell Growth & Diff. 3:645-654 (1992). A cysteine-free
region in the murine Cyr61 amino acid sequence is found between
amino acid residues 164 to 226 (SEQ ID NO:2). A corresponding
cysteine-free region is found in the human Cyr61 amino acid
sequence between amino acid residues 163 to 229 (SEQ ID NO:4). More
particularly, the mouse and human Cyr61 proteins are most divergent
between Cyr61 amino acids 170-185 and 210-225. Other members of the
ECM signaling molecule family of cysteine-rich proteins, e.g.,
Fisp12 (SEQ ID NO:6) and CTGF (SEQ ID NO:8), exhibit similar
structures suggestive of secreted proteins having sequences
dominated by cysteine residues.
[0113] Because murine Cyr61 contains 38 cysteines in the 355 amino
acid secreted portion, the contribution of disulfide bond formation
to Cyr61 tertiary structure was investigated. Exposure of Cyr61 to
10 mM dithiothreitol (DTT) for 16 hours did not affect the ability
of Cyr61 to mediate cell attachment (see below). However, Cyr61 was
inactivated by heating at 75.degree. C. for 5 minutes, by
incubation in 100 mM HCl, or upon extensive digestion with
chymotrypsin. These results indicate that murine Cyr61 is a heat-
and acid-labile protein whose active conformation is not sensitive
to reducing agents. The aforementioned structural similarities of
murine and human Cyr61 polypeptides suggests that human Cyr61 may
also be sensitive to heat or acid, but insensitive to reducing
agents. In addition, Cyr61 is neither phosphorylated nor
glycosylated.
[0114] To determine if the purified recombinant murine Cyr61
described above was the same as native murine Cyr61, two additional
characteristics of mouse Cyr61 were determined. First, two
independent protein fingerprints of recombinant and native murine
Cyr61 were obtained. Purified recombinant murine Cyr61 and a lysate
of serum-stimulated 3T3 cells, known to contain native murine
Cyr61, were subjected to limited proteolysis with either trypsin or
chymotrypsin, and their digestion products were compared. Partial
tryptic digests of both the recombinant protein and cell lysate
resulted in two Cyr61 fragments of approximately 21 and 19 kDa.
Similarly, fingerprinting of both preparations by partial
chymotrypsin digestion produced stable 23 kDa fragments from
recombinant murine Cyr61 and native murine Cyr61.
[0115] Another criterion used to assess the properties of
recombinant Cyr61 was its ability to bind heparin, described below.
Purified recombinant murine Cyr61 bound quantitatively to
heparin-sepharose at 0.15 M NaCl and was eluted at 0.8-1.0 M NaCl.
This heparin binding capacity is similar to native murine Cyr61
obtained from serum-stimulated mouse fibroblasts. Because of the
similarities of the murine and human Cyr61 proteins, recombinant
human Cyr61 should exhibit properties similar to the native human
Cyr61, as was the case for the murine polypeptides.
[0116] The polypeptides of the invention also extend to fragments,
analogs, and derivatives of the aforementioned full-length ECM
signaling molecules such as human and mouse Cyr61. The invention
contemplates peptide fragments of ECM signaling molecules that
retain at least one biological activity of an ECM signaling
molecule, as described above. Candidate fragments for retaining at
least one biological activity of an ECM signaling molecule include
fragments that have an amino acid sequence corresponding to a
conserved region of the known ECM signaling molecules. For example,
fragments retaining one or more of the conserved cysteine residues
of ECM signaling molecules would be likely candidates for ECM
signaling molecule fragments that retain at least one biological
activity. Beyond the naturally occurring amino acid sequences of
ECM signaling molecule fragments, the polypeptides of the invention
include analogs of the amino acid sequences or subsequences of
native ECM signaling molecules.
[0117] ECM signaling molecule analogs are polypeptides that differ
in amino acid sequence from native ECM signaling molecules but
retain at least one biological activity of a native ECM signaling
molecule, as described above. These analogs may differ in amino
acid sequence from native ECM signaling molecules, e.g., by the
insertion, deletion, or conservative substitution of amino acids. A
conservative substitution of an amino acid, i.e., replacing an
amino acid with a different amino acid of similar properties (e.g..
hydrophilicity, degree and distribution of charged regions) is
recognized in the art as typically involving a minor change. These
minor changes can be identified, in part, by considering the
hydropathic index of amino acids, as understood in the art. Kyle et
al., J. Mol. Biol. 157:105-132 (1982). The hydropathic index of an
amino acid is based on a consideration of its hydrophobicity and
charge, and include the following values: alanine (+1.8), arginine
(-4.5), asparagine (-3.5), aspartate (-3.5), cysteine/cystine
(+2.5), glycine (-0.4), glutamate (-3.5), glutamine (-3.5),
histidine (-3.2), isoleucine (+4.5), leucine (+3.8), lysine (-3.9),
metbionine (+1.9), phenylalanine (+2.8), proline (-1.6), serine
(-0.8), threonine (-0.7), tryptophan (-0.9), tyrosine (-1.3), and
valine (+4.2). It is known in the art that amino acids of similar
hydropathic indexes can be substituted and still retain protein
function. Preferably, amino acids having hydropathic indexes of
.+-.2 are substituted.
[0118] The hydrophilicity of amino acids can also be used to reveal
substitutions that would result in proteins retaining biological
function. A consideration of the hydrophilicity of amino acids in
the context of a polypeptide permits calculation of the greatest
local average hydrophilicity of that polypeptide, a useful measure
that has been reported to correlate well with antigenicity and
immunogenicity. U.S. Pat. No. 4,554,101, incorporated herein by
reference. Hydrophilicity values for each of the common amino
acids, as reported in U.S. Pat. No. 4,554,101, are: alanine (-0.5),
arginine (+3.0), asparagine (+0.2), aspartate (+3.0.+-.1), cysteine
(-1.0), glycine (0), glutamate (+3.0.+-.1), glutamine (+0.2),
histidine (-0.5), isoleucine (-1.8), leucine (-1.8), lysine (+3.0),
methionine (-1.3), phenylalanine (-2.5), proline (-0.5.+-.1),
serine (+0.3), threonine (-0.4), tryptophan (-3.4), tyrosine
(-2.3), and valine (-1.5). Substitution of amino acids having
similar hydrophilicity values can result in proteins retaining
biological activity, for example immunogenicity, as is understood
in the art. Preferably, substitutions are performed with amino
acids having hydrophilicity values within .+-.2 of each other. Both
the hydrophobicity index and the hydrophilicity value of amino
acids are influenced by the particular side chain of that amino
acid. Consistent with that observation, amino acid substitutions
that are compatible with biological function are understood to
depend on the relative similarity of the amino acids, and
particularly the side chains of those amino acids, as revealed by
the hydrophobicity, hydrophilicity, charge, size, and other
properties.
[0119] Additionally, computerized algorithms are available to
assist in predicting amino acid sequence domains likely to be
accessible to an aqueous solvent. These domains are known in the
art to frequently be disposed towards the exterior of a protein,
thereby potentially contributing to binding determinants, including
antigenic determinants. Having the DNA sequence in hand, the
preparation of such analogs is accomplished by methods well known
in the art (e.g., site-directed) mutagenesis and other
techniques.
[0120] Derivatives of ECM signaling molecules are also contemplated
by the invention. ECM signaling molecule derivatives are proteins
or peptides that differ from native ECM signaling molecules in ways
other than primary structure (i.e., amino acid sequence). By way of
illustration, ECM signaling molecule derivatives may differ from
native ECM signaling molecules by being glycosylated, one form of
post-translational modification. For example, polypeptides may
exhibit glycosylation patterns due to expression in heterologous
systems. If these polypeptides retain at least one biological
activity of a native ECM signaling molecule, then these
polypeptides are ECM signaling molecule derivatives according to
the invention. Other ECM signaling molecule derivatives include,
but are not limited to, fusion proteins having a covalently
modified- or C-terminus, PEGylated polypeptides, polypeptides
associated with lipid moieties, alkylated polypeptides,
polypeptides linked via an amino acid side-chain functional group
to other polypeptides or chemicals, and additional modifications as
would be understood in the art. In addition, the invention
contemplates ECM signaling molecule-related polypeptides that bind
to an ECM signaling molecule receptor, as described below.
[0121] The various polypeptides of the present invention, as
described above, may be provided as discrete polypeptides or be
linked, e.g., by covalent bonds, to other compounds. For example,
immunogenic carriers such as Keyhole Limpet Hemocyanin may be bound
to a ECM signaling molecule of the invention.
EXAMPLE 9
Heparin Binding Assay
[0122] The heparin binding assay for native murine Cyr61, described
in Yang et al., was modified for the purified recombinant murine
protein. Initially, recombinant purified Cyr61 was suspended in
RIPA (Radioimmunoprecipitation assay) buffer (150 mM NaCl, 1.0%
NP-40, 0.5% deoxycholate, 0.1% SDS, 50 mM Tris-HCl, pH 8.0, 1 mM
phenylmethylsulfonyl fluoride). Next, 200 .mu.l of a 50% (v/v)
slurry of heparin-Sepharose CL 6B beads (Pharmacia-LKB
Biotechnology, Inc., Piscataway, N.J.) was added to 100 .mu.l of
the recombinant Cyr61 solution and incubated for 1 hour. Under
these conditions, human Cyr61 was quantitatively bound to
heparin-agarose. Application of a salt concentration gradient in
RIPA buffer resulted in the elution of recombinant murine Cyr61 at
0.8-1.0 M NaCl. The elution profile of the recombinant protein was
similar to the elution profile for native murine Cyr61.
[0123] One might expect that Fisp12 would bind heparin with lower
affinity than Cyr61, as it does not interact with the ECM as
strongly as Cyr61. To examine this possibility, metabolically
labeled ([.sup.35S]-cysteine; 100 .mu.Ci per 100 mm dish; ICN) cell
lysates were incubated with heparin agarose beads which were
subsequently washed to remove unbound proteins. Bound proteins were
eluted in increasing salt concentrations. Fisp12 from cell lysates
was retained on heparin agarose but was eluted by 0.2 to 0.6 M NaCl
with peak elution at 0.4 M NaCl. This is in contrast to Cyr61,
which was eluted at significantly higher concentrations of NaCl.
This difference in heparin binding is consistent with the differing
affinities of Cyr61 and Fisp12 for the ECM, suggesting that binding
to heparan sulfate proteoglycans may be a primary mechanism by
which both proteins associate with the ECM.
EXAMPLE 10
Receptors
[0124] Human Cyr61, like murine Cyr61, was localized to the cell
surface and ECM. The localization of Cyr61 to the cell surface
implicated a cell surface receptor binding Cyr61. Consistent with
that implication, the biological effects of Cyr61 are mediated by
the .alpha..sub.V.beta..sub.3 integrin, or vitronectin receptor.
The .alpha..sub.V.beta..sub.3 integrin, in association with other
integrins, forms protein clusters providing focal points for
cytoskeletal attachment. Cyr61 induces the formation of protein
clusters, including the protein clusters containing the
.alpha..sub.V.beta..sub.3 integrin. In addition, using an in vitro
assay, the biological effects of Cyr61, including Cyr61-induced
cell adhesion and mitogenesis, were abolished by the addition of
either one of two monoclonal antibodies- LM609 (Cheresh. Proc.
Natl. Acad. Sci. [USA] 84:6471-6475 (1987]) or anti-VnR 1 (Chen el
al., Blood 86:2606-2615 [1995]) directed to the
.alpha..sub.V.beta..sub.3 integrin. This data led to the
identification of the .alpha..sub.V.beta..sub.3 integrin as the
Cyr61 receptor.
[0125] Cyr61 induction of HUVE cell adhesion, described in Example
13 below, led to an investigation of the divalent cation-sensitive
cell surface receptors expressed by HUVE cells. The cell adhesion
properties of Cyr61 were used to identify the receptor, which is a
divalent cation-sensitive cell surface receptor. The ability of
Cyr61 to mediate cell adhesion, coupled with the strict requirement
for divalent cations in the process, indicated that Cyr61 interacts
with one of the divalent cation-dependent cell adhesion molecules
from the integrin, selectin, or cadherin families. Ruoslahti et
al., Exp. Cell Res. 227:1-11 (1996). Using well-characterized
approaches to receptor identification, a series of inhibition
studies were conducted. Inhibitors, or blocking agents, of various
degrees of specificity (EDTA, similar to the EGTA described above;
inhibitory peptides bearing variants of the RGD (single letter
amino acid code) integrin recognition motif, such as RGDS, SGDR,
and RGDSPK (Ruoslahti, et al., Science 238:491-497 [1987],
Ruoslahti. E., Ann. Rev. of Cell and Dev. Biol. 12:698-715 [1996]);
and known, specific anti-receptor antibodies) were used to identify
a Cyr61 receptor. That receptor was the .alpha..sub.V.beta..sub.3
integrin, also known to function as the vitronectin receptor.
Confirmation of that identification was obtained by showing that
antibody LM609, a specific anti-.alpha..sub.V.beta..sub.3 integrin
antibody, could block the effect of Cyr61 on cell adhesion.
Integrins form a large family of heterodimeric adhesion receptors,
with a broad ligand specificity range, involved in cell-cell and
cell-matrix interactions. Beyond their requirement for divalent
cations and their involvement in cell-matrix adhesion events
[Hynes, R. O., Cell 69:11-25 (1992)], integrins also are involved
in cell migration [Damsky et al., Curr. Opin. Cell Biol. 4:772-781
(1992); Doerr et al., J. Biol. Chem. 271:2443-447 (1996)] and
proliferation [Juliano et al., J. Cell Biol., 120:577-585 (1993);
Plopper et al., Mol. Biol. Cell 6.1349-1365 (1995); and Clark et
al., Science 268:233-239 (1995)], two additional processes
associated with Cyr61 activity. The .alpha..sub.V.beta..sub.3
integrin was found to be essential for Cyr61-mediated cell
adhesion.
[0126] Characterization of CTGF binding to cells has been reported
to occur through a cell surface receptor that also interacts with
PDGF-BB (the BB isoform of PDGF), as recited in U.S. Pat.
No.5,408,040, column 11, line 10, to column 12, line 14,
incorporated herein by reference. The identification of the
foregoing receptors permits the design and production of molecules
and which bind to the respective receptors to inhibit the
activities of ECM molecules.
EXAMPLE 11
Anti-ECM Signaling Molecule Antibodies
[0127] Antibodies, optionally attached to a label or to a toxin as
described below, are also contemplated by the present invention.
The availability of the human cyr61 cDNA sequence and the Cyr61
deduced protein sequence facilitate the implementation of methods
designed to elicit anti-Cyr61 antibodies using a number of
techniques that are standard in the art. Harlow et al.
[0128] In one embodiment, polyclonal antibodies directed against
Cyr61 are generated. The generation of anti-Cyr61 antibodies
specific for human Cyr61, for example, is optimized by designing
appropriate antigens. The human Cyr61 protein is 381 amino acids
long, including the N-terminal secretory signal. As described
above, human Cyr61 exhibits a 91% amino acid sequence identity with
the 379 amino acid sequence of the mouse protein. However, the
mouse and human proteins diverge most significantly in the central
portion of the proteins, where they are devoid of cysteines (see
above). These sequence differences are exploited to elicit
antibodies specific to the human Cyr61 by using as an antigen a
peptide having a sequence derived from one of the divergent regions
in the human protein, although antibodies directed to a conserved
region are also contemplated by the invention.
[0129] In another embodiment of the present invention, monoclonal
antibodies are elicited using intact recombinant human Cyr61
although a fragment may be used. Female BALB/c mice are inoculated
intraperitoneally with a mixture of 0.25 ml recombinant human Cyr61
(5-50 micrograms), bacterially produced or produced in eukaryotic
cells, and 0.25 ml complete Freund's adjuvant. Fourteen days later
the injections are repeated with the substitution of incomplete
Freund's adjuvant for complete Freund's adjuvant. After an
additional two weeks, another injection of human Cyr61 in
incomplete Freund's adjuvant is administered. About two weeks after
the third injection, tail bleeds are performed and serum samples
are screened for human anti-Cyr61 antibodies by immunoprecipitation
with radiolabeled recombinant human Cyr61. About two months after
the initial injection, mice whose sera yield the highest antibody
titers are given booster injections of Cyr61 (5-50 micrograms in
incomplete Freund's adjuvant, 0.1 ml intravenously and 0.1 ml
intraperitoneally). Three days after the booster injection, the
mice are sacrificed. Splenocytes are then isolated from each mouse
using standard techniques, and the cells are washed and
individually fused with a myeloma cell line, e.g., the X63Ag8.653
cell line (Harlow et al.), using polyethylene glycol, by techniques
that are known in the art. Other suitable cell lines for fusion
with splenocytes are described in Harlow et al., at page 144, Table
6.2, incorporated herein by reference. Fused cells are removed from
the PEG solution, diluted into a counter-selective medium (e.g.,
Hypoxanthine-Aminopterin-Thymidine or HAT medium) to kill unfused
myeloma cells, and inoculated into multi-well tissue culture
dishes.
[0130] About 1-2 weeks later, samples of the tissue culture
supernatants are removed from wells containing growing hybridomas,
and tested for the presence of anti-Cyr61 antibodies by binding to
recombinant human Cyr61 bound to nitrocellulose and screening with
labeled anti-immunoglobulin antibody in a standard antibody-capture
assay. Cells from positive wells are grown and single cells are
cloned on feeder layers of splenocytes. The cloned cell lines are
stored frozen. Monoclonal antibodies are collected and purified
using standard techniques, e.g., hydroxylapatite chromatography. In
an alternative, Cyr61 peptides used as antigens, may be attached to
immunogenic carriers such as keyhole limpet hemocyanin carrier
protein, to elicit monoclonal anti-Cyr61 antibodies.
[0131] Another embodiment involves the generation of antibody
products against a fusion protein containing part, or all, of human
Cyr61, including enough of the protein sequence to exhibit a useful
epitope in a fusion protein. The fusion of the large subunit of
arithranilatc synthase (i.e., TrpE) to murine Cyr61, and the fusion
of glutathione S-transferase (i.e., GST) to murine Cyr61, have been
used to successfully raise antibodies against murine Cyr61. Yang et
al. In addition, a wide variety of polypeptides, well known to
those of skill in the art, may be used in the formation of Cyr61
fusion polypeptides according to the invention.
[0132] More particularly, Yang reported a TrpE-Cyr61 fusion
polypeptide that was expressed from a recombinant clone constructed
by cloning a fragment of the murine cyr61 cDNA containing
nucleotide 456 through nucleotide 951 (encoding Cyr61 amino acids
93-379) into the SacI site of the pATH1 vector. Dieckman et al., J.
Biol. Chem. 260:1513-1520 (1985). The recombinant construct was
transformed into a bacterial host, e.g., E. coli K12, and
expression of the fusion protein was induced by addition of 25
.mu.g/ml indoleacrylic acid to growing cultures. Subsequently,
cells were lysed and total cell lysate was fractionated by
electrophoresis on a 7.5% polyacrylamide gel. The fusion protein of
predicted size was the only band induced by indoleacrylic acid;
that band was eluted from the gel and used as an antigen to
immunize New Zealand White rabbits (Langshaw Farms) using
techniques that are standard in the art. Harlow et al. In addition
to polyclonal antibodies, the invention comprehends monoclonal
antibodies directed to such fusion proteins.
[0133] In other embodiments of the invention, recombinant antibody
products are used. For example, chimeric antibody products,
"humanized" antibody products, and CDR-grafted antibody products
are within the scope of the invention. Kashmiri et al., Hybridoma
14:461-473 (1995), incorporated herein by reference. Also
contemplated by the invention are antibody fragments. The antibody
products include the aforementioned types of antibody products used
as isolated antibodies or as antibodies attached to labels. Labels
can be signal-generating enzymes, antigens, other antibodies,
lectins, carbohydrates, biotin, avidin, radioisotopes, toxins,
heavy metals, and other compositions known in the art; attachment
techniques are also well known in the art.
[0134] Anti-Cyr61 antibodies are useful in diagnosing the risk of
thrombosis, as explained more fully in Example 20 below. In
addition, anti-Cyr61 antibodies are used in therapies designed to
prevent or relieve undesirable clotting attributable to abnormal
levels of Cyr61. Further, antibodies according to the invention can
be attached to toxins such as ricin using techniques well known in
the art. These antibody products according to the invention are
useful in delivering specifically-targeted cytotoxins to cells
expressing Cyr61, e.g., cells participating in the
neovascularization of solid tumors. These antibodies are delivered
by a variety of administrative routes, in pharmaceutical
compositions comprising carriers or diluents, as would be
understood by one of skill in the art.
[0135] Antibodies specifically recognizing Fisp12 have also been
elicited using a fusion protein. The antigen used to raise
anti-Fisp12 antibodies linked glutathione-S-transferase (GST) to
the central portion of Fisp12 (GST-Fisp12), where there is no
sequence similarity to Cyr61 (O'Brien and Lau, 1992). A construct
containing cDNA encoding amino acids 165 to 200 of Fisp12 was fused
to the glutathione-S-transferase (GST) coding sequence. This was
done by using polymerase chain reaction (PCR) to direct synthesis
of a fragment of DNA encompassing that fragment of fisp12 flanked
by a 5' BamHI restriction site and a 3' EcoRI restriction site. The
5' primer has the sequence 5'-GGGGATCTGTGACGAGCCCAAGGAC-3' (SEQ ID
NO:9) and the 3' primer has the sequence
5'-GGGAATTCGACCAGGCAGTTGGCTCG- -3' (SEQ ID NO:10). For
Cyr61-specific antiserum, a construct fusing the central portion of
Cyr61 (amino acids 163 to 229), which contains no sequence
similarity to Fisp12, to GST was made in the same manner using the
5' primer 5'-GGGGATCCTGTGATGAAGACAGCATT-3' (SEQ ID NO:11) and the
3' primer 5'-GGGAATTCAACGATGCATTTCTGGCC-3' (SEQ ID NO:12). These
were directionally cloned into pGEX2T vector (Pharmacia-LKB, lnc.)
and the clones confirmed by sequence analysis. The GST-fusion
protein was isolated on glutathione sepharose 4B (Pharmacia-LKB,
Inc.) according to manufacturer's instructions, and used to
immunize New Zealand white rabbits. For affinity purifications,
antisera were first passed through a GST-protein affinity column to
remove antibodies raised against GST, then through a GST-Fisp12 or
GST-Cyr61 protein affinity column to isolate anti-Fisp12 or
anti-Cyr61 antibodies (Harlow et al., [1988]).
[0136] These antibodies immunoprecipitated the correct size Fisp12
protein product synthesized in vitro directed by fisp12 mRNA. The
antibodies are specific for the Fisp12 polypeptide and show no
cross-reactivity with Cyr61.
[0137] Polyclonal antibodies recognizing CTGF are also known. U.S.
Pat. No. 5,408,040, column 7, line 41, to column 9, line 63,
incorporated by reference hereinabove, reveals an immunological
cross-reactivity between PDGF and CTGF, as described above.
EXAMPLE 12
Inhibitory Peptides
[0138] Another embodiment of the present invention involves the use
of inhibitory peptides in therapeutic strategies designed to
inhibit the activity of the Cyr61 protein. One approach is to
synthesize an inhibitory peptide based on the protein sequence of
Cyr61. For example, a peptide comprising an amino acid sequence
that is conserved between murine Cyr61 (SEQ ID NO:2) and human
Cyr61 (SEQ ID NO:4) competes with native Cyr61 for its binding
sites. This competition thereby inhibits the action of native
Cyr61. For example, administration of an inhibitory peptide by
well-known routes inhibits the capacity of Cyr61 to influence the
cascade of events resulting in blood clots, the vascularization of
tumors, or the abnormal vascularization of the eye (e.g., eye
disorders characterized by vascularization of the retina or the
vitreous humor), etc. In particular, an inhibitory peptide prevents
Cyr61 from inhibiting the action of Tissue Factor Pathway
Inhibitor, or TFPI, as described below.
[0139] In an embodiment of the invention, inhibitory peptides were
designed to compete with Cyr61. These inhibitory peptides, like the
antibodies of the preceding Example, exemplify modulators of Cyr61
activity, as described in the context of a variety of assays for
Cyr61 activity that are disclosed herein. The peptide design was
guided by sequence comparisons among murine Cyr61, Fisp12, and Nov
(an avian proto-oncogene). The amino acid sequences of several
members of this family are compared in FIG. 1. These types of
sequence comparisons provide a basis for a rational design for a
variety of inhibitory peptides. Some of these designed peptides,
for example peptides spanning amino acids 48-68 (SEQ ID NO:13),
115-135 (SEQ ID NO:14), 227-250 (SEQ ID NO:15), 245-270 (SEQ ID
NO:16), and 310-330 (SEQ ID NO:17) of SEQ ID NO:2, have been
synthesized. A comparison of the murine Cyr61 amino acid sequence
and the human Cyr61 amino acid sequence reveals that similar
domains from the human protein may be used in the design of
peptides inhibiting human Cyr61. In addition, sequence comparisons
may involve the human Cyr61 amino acid sequence; comparisons may
also include the human homolog of Fisp12, Connective Tissue Growth
Factor, also identified as a member of this protein family. O'Brien
et al. (1992).
[0140] Inhibitory peptides may also be designed to compete with
other ECM signaling molecules, eg., Fisp12 or CTGF, for binding to
their respective receptors. The design of inhibiting peptides is
facilitated by the similarity in amino acid sequences among the ECM
signaling molecules. In addition, inhibitory peptide design may be
guided by one or more of the methods known in the art for
identifying amino acid sequences likely to comprise functional
domains (e.g., hydrophilic amino acid sequences as external/surface
protein domains; sequences compatible with .alpha.-helical
formation as membrane-spanning domains). These methods have been
implemented in the form of commercially available software, known
to those of ordinary skill in the art. See e.g., the
Intelligenetics Suite of Analytical Programs for Biomolecules.
Intelligenetics, Inc., Mountain View, Calif. Using these
approaches, inhibitory peptides interfering with the biological
activity of an ECM signaling molecule such as Cyr61, Fisp12 or
CTGF, may be designed. With the design of the amino acid sequence
of an inhibitory peptide, production of that peptide may be
realized by a variety of well-known techniques including, but not
limited to, recombinant production and chemical synthesis.
Exemplary peptides that have been shown to specifically inhibit at
least one biological activity of Cyr61 include peptides exhibiting
the "RGD" motif, or motif variants such as "RGDS," "RGDSPK," "GDR,"
or "SGDR," (Ruoslahti, et al., Science 238:491-497 [1987],
Ruoslahti, E., Ann. Rev. of Cell and Dev. Biol. 12:698-715 [1996])
as described in Example 10 above.
EXAMPLE 13
Cell Adhesion
[0141] Another embodiment of the invention is directed to the use
of Cyr61 to mediate cellular attachment to the extracellular
matrix. Induction of cellular adhesion was investigated using
murine Cyr61, fibronectin, and bovine serum albumin (BSA).
Immunological 96-well plates (Falcon brand) were coated with 50
.mu.l of 0.1% BSA in PBS at 4.degree. C. in the presence of 0-30
.mu.g/ml concentrations of murine Cyr61 or fibronectin. After two
hours exposure to the coating solution, non-diluted immune or
pre-immune antisera (30 .mu.l/well), or affinity-purified
anti-Cyr61 antibodies were added. For some wells, the coating
mixture was adjusted to 10 mM DTT or 100 mM HCl. After 16 hours
incubation, the coating solution was removed and the well surface
was blocked with 1% BSA in phosphate-buffered saline (PBS) for 1
hour at room temperature. HUVE cells were plated in Ham's complete
F12K medium [GIBCO-BRL, Inc.; Ham, Proc. Natl. Acacd. Sci. (USA)
53:786 (1965)] at 5.times.10.sup.3-10.sup.4 cells/well.
Cycloheximide was added to 100 .mu.g/ml immediately before plating
and monensin was added to 1 .mu.M 14 hours before plating. After a
2-hour incubation at 37.degree. C., the wells were washed with PBS
and attached cells were fixed and stained with methylene blue. The
attachment efficiency was determined by quantitative dye extraction
and measurement of the extract absorbance at 650 nm. Oliver et al.,
J. Cell. Sci. 92:513-518 (1989).
[0142] HUVE cells attached poorly to dishes treated with BSA alone,
but adhered well to dishes coated with fibronectin. Murine
Cyr61-coated surfaces also supported HUVE cell attachment in a
dose-dependent manner, similar to fibronectin. For example, at 1
.mu.g/ml, Cyr61 and fibronectin yielded A.sub.650 values of 0.1. An
A.sub.650 value of 0.5 corresponded to the attachment of
6.times.10.sup.3 cells. At the other end of the tested
concentration range, 30 .mu.g/ml, Cyr61 yielded an A.sub.650 of
0.8: fibronectin yielded an A.sub.650 of 0.9. Cyr61 also promoted
the attachment of NIH 3T3 cells, though less effectively than
fibronectin. Cyr61-mediated cell attachment can be observed as
early as 30 minutes after plating, as visualized by light
microscopy.
[0143] The adhesion of HUVE cells on murine Cyr61-coated surfaces
was specifically inhibited by anti-Cyr61 antiserum and by
affinity-purified anti-Cyr61 antibodies, but not by pre-immune
serum. In contrast, attachment of cells to fibronectin-coated
dishes was not affected by either the anti-Cyr61 antiserum or
affinity-purified anti-Cyr61 antibodies. These results show that
enhancement of cell adhesion is a specific activity of the Cyr61
protein. Furthermore, the Cyr61-mediated cell attachment was
insensitive to cycloheximide or monensin treatment, indicating that
Cyr61 does not act by inducing de novo synthesis of ECM components,
stimulation of fibronectin, or collagen secretion. Rather, the data
support the direct action of Cyr61 on cells in effecting adhesion.
The Cyr61-mediated attachment of HUVE cells was completely
abolished by the presence of EGTA; however, attachment was restored
by the addition of CaCl.sub.2 or MgSO.sub.4 to the medium. These
results indicate that the interaction between Cyr61 and its cell
surface receptor requires divalent cations, consistent with the
observations leading to the identification of the
.alpha..sub.V.beta..sub.3 integrin as the Cyr61 receptor described
in Example 10, above.
[0144] The ability of Cyr61 to promote cell adhesion, and the
ability of molecules such as anti-Cyr61 antibodies to inhibit that
process is exploited in an assay for modulators of cell adhesion.
The assay involves a comparison of cell adhesion to surfaces, e.g.,
plastic tissue culture wells, that are coated with Cyr61 and a
suspected modulator of cell adhesion. As a control, a similar
surface is coated with Cyr61 alone. Following contact with suitable
cells, the cells adhering to the surfaces are measured. A relative
increase in cell adhesion in the presence of the suspected
modulator, relative to the level of cell adherence to a
Cyr61-coated surface, identifies a promoter of cell adhesion. A
relative decrease in cell adhesion in the presence of the suspected
modulator identifies an inhibitor of cell adhesion.
[0145] The identification of a Cyr61 receptor led to the
development of a rapid and specific ligand-receptor assay (i.e.,
integrin binding assay) for Cyr61. Monoclonal antibody LM609
(anti-.alpha..sub.V.beta..sub.3) has been described. Cheresh, 1987.
Monoclonal antibody JBS5 (anti-fibronectin antibody) was purchased
from Chemicon. Anti-human and anti-bovine vitronectin antisera were
from Gibco BRL. HRP-conjugated goat anti-rabbit antibody was from
KPL. RGDSPK peptide was from Gibco BRL; RGDS and SDGR peptides were
from American Peptide Company. The peptides for functional assays
were dissolved in PBS at 10 mg/ml and the pH was adjusted to
7.5-8.0.with NaOH. Human plasma vitronectin was from Collaborative
Biomedical Products.
[0146] .alpha..sub.V.beta..sub.3 integrin purification from HUVE
cell lysates was done as described in Pytela et al., Meth.
Enzynmol., 144:475-489 (1987). Briefly, 10.sup.8 cells were lysed
in 1 ml of PBS containing 1 mM CaCl.sub.2, 1 mM MgCl.sub.2, 0.5 mM
PMSF and 100 mM octylglucoside. The lysate was passed four times
through a 0.5 ml column containing RGDSPK Sepharose (prepared from
the cyanogen bromide activated Sepharose CL 4B as described in Lam,
S. C-T., J. Biol. Chem., 267:5649-5655 (1992). The column was
washed with 10 ml of the lysis buffer and the bound protein was
eluted with 2 ml of the same buffer containing 1 mM RGDS peptide at
room temperature. The .alpha..sub.V.beta..sub.3 integrin was
dialyzed against PBS containing 1 mM CaCl.sub.2, 1 mM MgCl.sub.2, 5
mM octylglucoside and 0.1 mM PMSF with three changes of the
dialysis buffer to remove the RGDS peptide. The protein was stored
in aliquots at -70.degree. C. The purity of the integrin was
determined by SDS-PAGE under non-reducing conditions, followed by
silver staining. Western blotting with anti-CD47 antibody showed
that this .alpha..sub.V.beta..sub.3 integrin preparation does not
contain any integrin-associated proteins.
[0147] The integrin binding assay was developed in accordance with
the disclosures in Brooks et al., Cell 85:683-693 (1996), and Lam,
S. C-T (1992). Approximately 50 ng of the integrin in a total
volume of 50 .mu.l were added per well of 96-well immunological
Pro-Bind plates (Falcon) and incubated overnight at 4.degree. C.
Non-specific sites were blocked with 20 mg/ml BSA in the same
buffer and washed four times in that buffer. Treated plates were
incubated with 1 .mu.g/ml Cyr61 or 0.1 .mu.g/ml vitronectin for 3
hours at room temperature. EDTA (5 mM), RGDS peptide (0.5 mM) and
blocking antibodies were either preincubated with the immobilized
integrin for 1 hour before the addition of the protein ligand or
added along with the ligand. The final dilution of the LM609
ascites fluid was 1:200. Bound proteins were detected by specific
polyclonal antisera (anti-Cyr61 antiserum was diluted 1:500 and
anti-vitronectin antiserum was diluted 1:1000 in PBS containing 1
mM CaCl.sub.2, 1 mM MgCl.sub.2, and 5 mg/ml BSA) followed by a
secondary antibody-horseradish peroxidase conjugate (1:20000 in the
same buffer). Plates were rinsed four times with PBS containing 1
mM CaCl.sub.2 and 1 mM MgCl.sub.2 after each incubation.
Horseradish peroxidase (HRP) was detected with an HRP immunoassay
kit (Bio-Rad Laboratories). The colorimetric reaction was developed
for 15-30 minutes at room temperature, stopped by the addition of
H.sub.2SO.sub.4, and the absorbance at 450 nm was measured. Those
of ordinary skill in the art will understand that a variety of
detection techniques could be employed in place of the
enzyme-linked immunological approach exemplified. For example,
other labels such as radiolabels, fluorescent compounds and the
like could be bound, e.g., covalently, to an antibody or other
agent recognizing the peptide of interest such as Cyr61.
[0148] The results of integrin binding assays showed that
vitronectin and Cyr61 bound to the immobilized integrin. Further,
both Cyr61 and vitronectin binding to .alpha..sub.V.beta..sub.3
were saturable. The concentration of Cyr61 at which saturation was
reached was significantly higher than the concentration of
vitronectin required for saturation. This difference may reflect a
lower affinity of .alpha..sub.V.beta..sub.3 for Cyr61 compared to
vitronectin, which is in agreement with the results of cell
adhesion assays, which show that HUVE cells adhere to vitronectin
and, more weakly, to Cyr61, in a concentration-dependent manner
(see below). The specificity of the interaction was addressed by
blocking the ligand binding site of the integrin using any one of
several techniques, including divalent cation deprivation, RGDS
peptide competition, and LM609 antibody inhibition. The interaction
of both proteins (Cyr61 and vitronectin) with
.alpha..sub.V.beta..sub.3 was inhibited by EDTA, the RGDS peptide,
and the LM609 antibody. These properties of the Cyr61 interaction
with .alpha..sub.V.beta..sub.3 were also in agreement with the
results of the cell adhesion assay and indicated that HUVE cell
adhesion to Cyr61 was mediated by the direct interaction of Cyr61
with the .alpha..sub.V.beta..sub.3 integrin.
[0149] In addition, Cyr61 induces focal adhesion, i.e., cell
surface foci for cytoskeletal attachments. Focal adhesion is
effected by cell surface protein complexes or clusters. These
protein clusters are complex, including a variety of receptors from
the integrin family, and a variety of protein kinases. The
induction of focal adhesion by Cyr61 is reflected in the capacity
of Cyr61 to induce particular members of these cell surface protein
clusters. For example, Cyr61 induces the phosphorylation of Focal
Adhesion Kinase, a 125 kDa polypeptide, and Paxillin, another
protein known to be involved in the focal adhesion cell surface
protein complexes. Moreover, indirect immunofluorescence studies
have shown that Cyr61 is bound to a receptor (see above) in focal
adhesive plaques. The plaques, in turn, are characteristic of focal
adhesion protein complexes. Focal Adhesion Kinase, Paxillin, and
.alpha..sub.V.beta..sub.3 Integrin are co-localized to the focal
adhesion plaques produced by focal adhesion complex formation
induced by Cyr61. These focal adhesion protein complexes bind Cyr61
at the cell surface; the complexes also attach internally to the
cytoskeleton. Therefore, murine Cyr61, and human Cyr61 (see below),
are, in part, adhesion molecules, a characteristic distinguishing
Cyr61 from conventional growth factors. Those of skill in the art
will also recognize that the .alpha..sub.V.beta..sub.3 integrin can
be used, in conjunction with Cyr61,to screen for modulators of
Cyr61 binding to its receptor. In one embodiment, the integrin is
immobilized and exposed to either (a) Cyr61 and a suspected
modulator of receptor binding; or (b) Cyr61 alone. Subsequently,
bound Cyr61 is detected, e.g., by anti-Cyr61 antibody that is
labeled using techniques known in the art, such as radiolabelling,
fluorescent labeling, or the use of enzymes catalyzing calorimetric
reactions. A promoter of Cyr61 binding to its receptor would
increase binding of Cyr61 (and an inhibitor would decrease Cyr61),
relative to the binding by Cyr61 alone.
[0150] In another embodiment of the invention, the effect of murine
Cyr61 on cell morphogenesis was assessed by a cell spreading assay.
Polystyrene Petri dishes were coated with 2 ml of a 10 .mu.g/ml
solution of Cyr61 or fibronectin in PBS with 0.1% BSA and treated
as described above. A third plate was treated with BSA and served
as a control. Each dish received 7.times.10.sup.6 cells and was
incubated for 2 hours. Cell spreading was analyzed by microscopy at
100-fold magnification. The results indicate that murine Cyr61
induces HUVE cell spreading to approximately the same extent as
fibronectin. The efficient attachment (see above) and spreading of
cells on murine Cyr61-coated substrates indicated that Cyr61 may
interact with a signal-transducing cell surface receptor, leading
to a cascade of cytoskeletal rearrangements and possible formation
of focal contacts. Consequently, Cyr61 and Cyr61-related
polypeptides may prove useful in controlling cell adhesion, e.g.,
the cell adhesion events that accompany metastasizing cancer cells,
organ repair and regeneration, or chondrocyte colonization of
prosthetic implants, discussed below.
[0151] In contrast to mouse Cyr61 which mediated both HUVE cell
attachment and migration, hCyr61 was found to mediate cell adhesion
but not spreading of HUVE cells. Immunological plates (96-well
ProBind assay plates, Falcon) were coated with 0.1-30 .mu.g/ml
hCyr61, fibronectin (Gibco BRL) or vitronectin (Gibco BRL) in
phosphate-buffered saline (PBS) containing 0.1% protease-free BSA
(Sigma) for 16 hrs at 4.degree. C. The wells were blocked with 1%
BSA in PBS for 1 hr at room temperature and washed with PBS. HUVE
cells were harvested with 0.02% EDTA in PBS, washed twice with
serum-free F12 medium and resuspended in serum-free F12. In some
experiments, fbs was added to 5-10%. Also, in experiments involving
vitronectin-coateci plates, endogenous vitronectin was removed from
fbs by immunoaffinity chromatography using bovine polyclonal
anti-vitronectin antibodies (Gibco). Norris et al., J. Cell Sci.
95:255-262 (1990). Cells were plated at 10.sup.4 cells/well. After
2 hours, cells were fixed with 4% paraformaldehyde, stained with
methylene blue and quantified as described. Oliver et al., J. Cell
Sci. 92:513-518(1989).
[0152] Under serum-free conditions, hCyr61 mediated cell attachment
but not spreading of HUVE cells. Attachment of HUVE cells to
hCyr61-coated plates was enhanced by inclusion of serum in the
culture medium. In the presence of serum, HUVE cells attached and
spread on hCyr61 in a manner similar to that seen on fibronectin.
Human Cyr61 supported HUVE cell adhesion in a dose-dependent manner
both under high-serum (10%) and low-serum (0.5%) conditions.
However, in the presence of 10% fbs, the maximal proportion of the
cells attaching at a lower concentration of hCyr61, and the
proportion of the cells attached, was higher. Human Cyr61 was also
found to cooperate with vitronectin in promoting HUVE cell adhesion
and spreading. Two major cell-adhesive proteins found in mammalian
sera are fibronectin and vitronectin, also known as "serum
spreading factor." For review, see Felding-Habermann et al., Curr.
Opin. Cell Biol. 5:864-868 (1993). Cell attachment, spreading and
growth on tissue-culture plastic depended upon vitronectin, rather
than fibronectin, in serum for the following reasons: (1)
considerable depletion of fibronectin in the batches of fbs due to
"clotting" at 4.degree. C.; and (2) inability of fibronectin to
efficiently coat the plastic in the presence of an excess amount of
other serum proteins. In contrast, vitronectin coated the plastic
surfaces efficiently under the same conditions.
[0153] The ability of HUVE cells to adhere to hCyr61-coated plates
in the presence of mock-immunodepleted fbs and serum immunodepleted
with anti-bovine vitronectin antibodies were compared. HUVE cells
adhered to hCyr61-coated surfaces significantly better in the
presence of soluble vitronectin or mock-immunodepleted fbs than
they did in the presence of serum-free medium or medium
supplemented with vitronectin-immunodepleted fbs. The addition of
vitronectin (30 .mu.g/ml) to vitronectin-immunodeple- ted serum
restored the ability of HUVE cells to adhere and spread on
hCyr61-coated plates to the same level observed when whole serum
was used in the cell attachment assay. Furthermore, soluble
vitronectin alone, at a concentration equal to its level in 10%
serum (30 .mu.g/ml), restored the level of cell adhesion and
spreading to the level found in the presence of 10% serum. Thus,
vitronectin is a necessary and sufficient serum component
contributing to HUVE cell adhesion and spreading on hCyr61-coated
plastic surfaces. Control studies showed that the effect of
vitronectin was not due to its preferential retention on the
plastic dish surfaces in the presence of hCYR61.
[0154] Additionally, HUVE cell attachment and spreading in the
presence of an increasing quantity of vitronectin was examined. The
solutions for coating the dishes contained increasing amounts of
vitronectin (0-10 .mu.g/ml) with a fixed amount of hCyr61 (10
.mu.g/ml). The results indicated that more cells adhered to plates
coated with the two proteins than would have been expected by
adding the individual adhesive capacities of vitronectin and
hCyr61. This non-additive increase of adhesion in the presence of
vitronectin and hCyr61 was not due to higher amounts of vitronectin
absorbed on the plastic. ELISA assay with anti-human vitronectin
antibodies showed that the amount of vitronectin adsorbed to
plastic dishes exposed to the vitronectin/hCyr61 mixture did not
exceed that of vitronectin alone by more than 20%. This difference
is insufficient to explain the observed difference in cell adhesion
(3-5 fold in different experiments). In addition, a higher
proportion of HUVE cells also adhered to the mixture of proteins
when the coating solution contained diluted vitronectin (2.5
.mu.g/ml) than were found to adhere to dishes coated with higher
concentrations of pure vitronectin (10 .mu.g/ml) or pure hCyr61 (10
.mu.g/ml). Thus, vitronectin and hCyr61 functionally cooperate and
exert a synergistic effect on HUVE cell adhesion.
[0155] The capacity of Fisp12 to affect cell adhesion was also
investigated. Fisp12 cell attachment assays were performed
essentially as described (Oliver et al., [1989]). 96-well
immunological plates were coated for 16 hours at 4.degree. C. with
20 .mu.g/ml Cyr61, Fisp12 or fibronectim (Gibco BRL) in PBS
containing 0.1 mg/ml BSA and blocked with 10 mg/ml BSA for 1 hour
at room temperature. HUVE cells were plated at 10.sup.4 cells/well
in F12K media with 10% FBS (Hyclone Laboratories, Inc., Logan,
Utah); NIH 3T3 fibroblasts were plated at 3.times.10.sup.4
cells/well and Mv1Lu cells were plated at 5.times.10.sup.4
cells/well in minimal essential medium (MEM) with 10% FBS. After 1
hour incubation cells were fixed, stained with methylene blue and
quantified as described (Oliver et al., [1989]). Cell spreading was
examined on cells plated on 100 mm polystyrene petri dishes coated
with 2.5 ml of a 20 .mu.g/ml solution of Cyr61, Fisp12 or
fibronectin. 10.sup.7 cells were plated on each dish and cell
spreading was analyzed 90 minutes after plating by microscopy at
100.times. magnification.
[0156] The results indicated that Fisp12, as well as Cyr61, when
coated on plastic dishes, promoted the attachment of three
different cell types: HUVE cells, NIH 3T3 fibroblasts, and mink
lung epithelial (Mv1Lu) cells. These cells attached poorly to
uncoated plastic dishes or plastic dishes coated with bovine serum
albumin, but attached significantly better to dishes coated with
either fibronectin, Cyr61, or Fisp12. The ability of either Cyr61
or Fisp12 to mediate cell attachment is comparable to that of
fibronectin for all three cell types. While the ability of Cyr61 to
mediate cell attachment was previously demonstrated for fibroblasts
and endothelial cells (Kireeva et al., Mol. Cell Biol. 16:1326-1334
[1996]), these studies show cell attachment activity for both
Fisp12 and Cyr61 in epithelial cells in addition to endothelial
cells and fibroblasts.
[0157] Like cell attachment to fibronectin and Cyr61 (Kireeva et
al., [1996]), Fisp12-mediated cell attachment was inhibited when
EDTA was added to the culture medium. This inhibition was
completely abolished by the addition of excess MgCl.sub.2,
indicating a requirement for divalent cations in Fisp12-mediated
cell attachment. In addition to cell attachment, Fisp12 also
promotes cell spreading. Similar cell spreading was found when NIH
3T3 cells were plated on dishes coated with either fibronectin,
Cyr61 or Fisp12, but not BSA. Endothelial and epithelial cells also
spread when plated on fibronectin, Cyr61, or Fisp12.
EXAMPLE 14
Migration of Fibroblasts
[0158] Cyr61 also affects chondrocytes, e.g., fibroblasts involved
in skeletal development. In particular, Cyr61 influences the
development, and perhaps maintenance, of cartilage, in contrast to
the variety of growth-related proteins that exclusively influence
development and maintenance of the bony skeleton. The chemotactic
response of NIH 3T3 cells to murine Cyr61 was examined using a
modified Boyden chamber (Neuroprobe Inc., catalog no. AP48).
Grotendorst, Meth. Enzymol. 147:144-152 (1987). Purified Cyr61
protein was serially diluted in DMEM containing bovine serum
albumin (BSA; 0.2 mg/ml) and added to the lower well of the
chamber. The lower well was then covered with a collagen-coated
polycarbonate filter (8 .mu.m pore diameter; Nucleopore Corp.,
Pleasanton, Calif.). Cells (6.times.10.sup.4) were then loaded into
the upper well. After 5 hours incubation (10% CO.sub.2, 37.degree.
C.), the filter was removed and the cells were fixed and stained
using Wright-Giemsa stain (Harleco formulation; EM Diagnostic
Systems, Gibbstown, N.J.). Cells from the upper surface of the
filter were then removed by wiping with a tissue swab. The
chemotactic response was determined by counting the total number of
migrating cells detected in ten randomly selected high-power
microscopic fields (400-fold magnification) on the lower surface of
the filter. Duplicate trials were performed for each experiment and
the experiment was repeated three times to ensure reproducibility
of the data.
[0159] NIH 3T3 cells responded to Cyr61 as a chemotactic factor in
a dose-dependent manner in the Boyden chamber assay. Without Cyr61,
approximately 4.8 cells had migrated per high-power field. In the
presence of 0.5 .mu.g/ml murine Cyr61, about 5.2 cells were found
in each field. As the concentration of Cyr61 was raised to 1, 5 and
10 .mu.g/ml, the average number of migrating cells detected per
field rose to 7.5, 18.5, and 18.7. Thus, murine Cyr61 acts as a
chemoattractant for fibroblasts. The optimal concentration for the
chemotactic activity of Cyr61 is 1-5 .mu.g/ml in this assay; this
concentration range is consistent with the reported ranges at which
other ECM molecules provide effective chemotactic stimulation. For
example, Thrombospondin, at 5-50 .mu.g/ml, has a chemotactic effect
on endothelial cells (Taraboletti et al., J. Cell Biol. 111:765-772
(1990); fibronectin also functions as a chemotactic agent at 1-30
.mu.g/ml (Carsons et al., Role of Fibronectin in Rheumatic
Diseases, in Fibronectin [Mosher, ed., Academic Press 1989];
Carsons et al., Arthritis. Rheum. 28:601-612 [1985]) as determined
using similar Boyden chamber assays. The human Cyr61 polypeptide
may be used to chemoattract fibroblasts in a manner analogous to
murine Cyr61. In experiments analogous to the studies of NIH 3T3
cell migration in response to murine Cyr61, the migration of 1064SK
human skin fibroblasts in response to wild-type human Cyr61 , and
human Cyr61 NT (a Cyr61 polypeptide fragment described in greater
detail in Example 29), was determined. Cyr61 induced migration of
the human fibroblast cells at comparable levels to the murine Cyr61
levels inducing NIH3T3 cell chemotaxis. The human Cyr61 NT induced
1064SK cell migration at levels comparable to the effective levels
of wild-type human Cyr61. Antibody studies showed that an antibody
specific for the .alpha..sub.V integrin subunit blocked fibroblast
migration in the presence of Cyr61 polypeptides, while an antibody
(i.e., GoH3) specific for the .alpha..sub.6 integrin subunit did
not block migration. Further investigation revealed that a
monoclonal antibody specifically recognizing the
.alpha..sub.V.beta..sub.5 integrin inhibited Cyr61-induced human
fibroblast migration, but a monoclonal antibody specifically
recognizing the integrin .alpha..sub.V.beta..sub.3 did not inhibit
that migration. Thus, integrin .alpha..sub.V.beta..sub.5 mediates
the fibroblast migration response to Cyr61 polypeptides. These
results contrast with the results of antibody studies analyzing the
chemotactic response of endothelial cells to Cyr61 polypeptides,
which is dependent on integrin .alpha..sub.V.beta..sub.3. Human
CTGF has also been reported to induce the migration of non-human
mammalian cells such as NIH 3T3 cells (mouse fibroblasts) and BASM
cells (bovine aortic smooth muscle cells), as described in U.S.
Pat. No. 5,408,040, column 7, line 65 to column 11, line 7,
incorporated herein by reference.
[0160] Thus, one aspect of the invention is a method of screening
for modulators of cell migration, such as fibroblast cell
migration. In general, the method involves exposing cells that
preferably present at least one suitable integrin receptor to a
Cyr61 polypeptide in the presence or absence of a potential, or
suspected, modulator. Subsequent measurement of relative cell
migration rates (in the presence and absence of the potential
modulator) identifies modulators of Cyr61-induced cell migration. A
variety of small chemicals, both inorganic and organic, as well as
various peptides, are expected to be potential modulators. Examples
include mannose and its derivative, mannose-6-phosphate, with the
latter expected to function as a modulator of Cyr61-induced cell
migration by inhibition. The potential modulators screened by
methods of the invention can have any of a wide variety of
structures and may be tested individually or as part of a more
systematic approach using any of the chemical or peptide libraries
known in the art.
[0161] In an alternative embodiment, an assay for modulators of
cell migration, such as the migration of chondrocytes, involves a
combination of a suspected modulator of cell migration and Cyr61
being added to the lower well of a Boyden chamber. As a control,
Cyr61 is separately added to the lower well of another Boyden
chamber. Relative cell migrations are then measured. An increase in
cell migration in the presence of the suspected modulator relative
to cell migration in response to Cyr61 alone identifies a promoter
of chondrocyte cell migration, while a relative decrease in cell
migration in the presence of the suspected modulator identifies an
inhibitor.
EXAMPLE 15
Migration of Endothelial Cells--In Vitro Assays
[0162] The end product of in vitro angiogenesis is a well-defined
network of capillary-like tubes. When cultured on gel matrices,
e.g., collagen, fibrin, or Matrigel gels, endothelial cells must
first invade the matrix before forming mature vessels. (Matrigel is
a complex mixture of basement membrane proteins including laminin,
collagen type IV, nidogen/entactin, and heparan sulfate
proteoglycan, with additional growth factors. Kleinman el al.,
Biochem. 25:312-318 (1986). The invasive structures are cords which
eventually anastomose to form the vessel-like structures. The
angiogenic effect of human Cyr61 on confluent monolayers of human
umbilical vein endothelial cells is assessed by seeding the cells
onto three-dimensional collagen or fibrin gels, in the presence or
absence of Cyr61. HUVE cels do not spontaneously invade such gels
but do so when induced by agents such as tumor promoters.
[0163] Collagen gels were prepared by first solubilizing type I
collagen (Collaborative Research, Inc., Bedford, Mass.) in a
sterile 1:1000 (v/v) dilution of glacial acetic acid (300 ml per
gram of collagen). The resulting solution was filtered through
sterile triple gauze and centrifuged at 16,000.times. g for 1 hour
at 4.degree. C. The supernatant was dialyzed against 0.1.times.
Eagle's Minimal Essential Medium (MEM; GIBCO-BRL, Inc.) and stored
at 4.degree. C. Gels of reconstituted collagen fibers were prepared
by rapidly raising the pH and ionic strength of the collagen
solution The pH and ionic strength adjustments were accomplished by
quickly mixing 7 volumes of cold collagen solution with one volume
of 10.times. MEM and 2 volumes of sodium bicarbonate (11.76 mg/ml)
in a sterile flask. The solution was kept on ice to prevent
immediate gelation. The cold mixture was dispensed into 18 mm
tissue culture wells and allowed to gel for 10 minutes at
37.degree. C.
[0164] Fibrin gels were prepared by dissolving fibrinogen (Sigma
Chemical Co.. St. Louis, Mo.) immediately before use in
calcium-free MEM to obtain a final concentration of 2.5 mg of
protein/ml. Clotting was initiated by rapidly mixing 1.35 ml of
fibrinogen solution with 15 .mu.l of 10.times. MEM containing 25
U/ml thrombin (Sigma Chemical Co.) in a plastic tube. The mixture
was transferred immediately into 18 mm tissue culture wells and
allowed to gel for about 2 minutes at 37.degree. C.
[0165] In some wells, Cyr61 was mixed into the gel matrix before
gelation (final concentration 10 .mu.g/ml), while in other wells,
Cyr61 was not in the gel matrix but was added as part of the
nutrient medium (similar range of concentrations as in the matrix)
after the cells reached confluency. HUVE cells were seeded onto the
gel matrix surface at 5.times.10.sup.4 cells per well in Ham's F12K
medium [GIBCO-BRL, Inc.] containing 10% fetal bovine serum, 100
.mu.g/ml heparin, and 30 .mu.g/ml endothelial cell growth factor.
When the cells reached confluency, the medium was removed, the
cells were rinsed with PBS, and fresh medium without endothelial
cell growth factor was supplied. Some cultures received purified
recombinant Cyr61, while others received Cyr61 and polyclonal
anti-Cyr61 antibodies. Thus, the variety of cultures at confluency
included: a) cultures with no Cyr61; b) cultures with Cyr61 within
the matrix; c) cultures with Cyr61 supplementing the medium; and d)
cultures with Cyr61 supplementing the medium along with polyclonal
anti-Cyr61 antibodies.
[0166] Invasion of the gel matrix was quantified about 4-7 days
after treatment of the confluent cultures. Randomly selected fields
measuring 1.0 mm.times.1.4 mm were photographed in each well under
phase-contrast microscopy with a Zeiss Axiovert inverted
photomicroscope. Photographs were taken at a single level beneath
the surface monolayer. Invasion was quantified by measuring the
total length of all cell cords that penetrated beneath the surface
monolayer. Results were expressed as the mean length in microns per
field for at least 3 randomly selected fields from each of at least
3 separate experiments.
[0167] In order to examine the network of cords within the matrix
for capillary-like tube formation, cultures were fixed in situ
overnight with 2.5% glutaraldehyde and 1% tannic acid in 100 mM
sodium cacodylate buffer, pH 7.4. Cultures were then washed
extensively in 100 mM sodium cacodylate buffer, pH 7.4. The gels
were cut into 2 mm.times.2 mm fragments, post-fixed in 1% osmium
tetroxide in veronal acetate buffer (to minimize tissue swelling;
see Hayat, in Principles and Techniques of Electron Microscopy,:
Biological Applications 1:38 [Litton Educational Publishing, Inc.
1970]) for 45 minutes, stained en bloc with 0.5% uranyl acetate in
veronal buffer for 45 minutes, dehydrated by exposure to a graded
ethanol series, and embedded in Epon in flat molds. Semi-thin
sections were cut perpendicular to the culture plane with an
ultramicrotome, stained with 1% toluidine blue, and photographed
under transmitted light using an Axiophot photomicroscope
(Zeiss).
[0168] In an alternative embodiment, a suspected modulator of
angiogenesis is combined with Cyr61 and the combination is added
before, or after, formation of a gel. In this embodiment, a control
is established by using Cyr61 alone. The migration of cells in
response to the suspected modulator and Cyr61 is then compared to
the migration of cells in response to Cyr61 alone. A promoter or
positive effector will increase cell migration while an inhibitor
or negative effector will decrease cell migration.
[0169] In an alternative in vitro assay for angiogenic activity, an
assay for endothelial cell migration was developed. This chemotaxis
assay has been shown to detect the effects of Cyr61 concentrations
on the order of nanograms per milliliter. Primary Human
Microvascular Endothelial Cells (HMVEC PO51, Clonetics, San Diego,
Calif.) were maintained in DME with 10% donor calf serum (Flow
Laboratories, McLean, Va.) and 100 .mu.g/ml endothelial celi
mitogen (Biomedical Technologies Inc., Stoughton, Mass.). The cells
were used between passages 10 and 15. To measure migration, cells
were starved for 24 hours in DME containing 0.1% BSA, harvested,
resuspended in DME with 0.1% BSA, and plated at 1.75.times.10.sup.4
cells/well on the lower surface of a gelatinized 0.5 .mu.m filter
(Nucleopore Corporation, Pleasanton. Calif.) in an inverted
modified Boyden chamber. After 1-2 hours at 37.degree. C., during
which time the cells were allowed to adhere to the filter, the
chamber was reverted to its normal position. To the top well of
separate chambers, basic Fibroblast Growth Factor (a positive
control), Cyr61, or a negative control solution (conditioned medium
known to lack chemoattractants or DME plus BSA, see below) was
added at concentrations ranging from 10 ng/ml to 10 .mu.g/ml.
Chambers were then incubated for 3-4 hours at 37.degree. C. to
allow migration. Chambers were disassembled, membranes fixed and
stained, and the number of cells that had migrated to the top of
the filter in 3 high-powered fields was determined. Tolsma et al.,
J. Cell. Biol. 122:497-511 (1993) (incorporated by reference), and
references cited therein. DME with 0.1% BSA was used as a negative
control and either bFGF (10 ng/ml) or conditioned media from
angiogenic hamster cell lines (20 .mu.g/ml total protein) were used
as positive controls. Rastinejad et al., Cell 56:345-355 (1989).
Each sample was tested in quadruplicate (test compound such as
Cyr61, positive control, conditioned medium as a negative control,
and DME plus BSA as a negative control) in a single experiment;
experiments were repeated at least twice.
[0170] To allow comparison of experiments performed on different
days, migration data is reported as the percent of maximum
migration towards the positive control, calculated after
subtraction of background migration observed in the presence of DME
plus BSA. Test compounds that depressed the random movement of
endothelial cells showed a negative value for the percent
migration. Very high concentrations of thrombospondin (TSP) caused
endothelial cells to detach from the membrane. Detachment was
detected by counting cells on the lower face of the membrane. When
cell loss exceeded 10%, the number of migrated cells was corrected
for this loss. The results indicate that 0.01-10 .mu.g/ml bFGF
induced the migration of a constant 92 cells per three high-powered
microscope fields Migration in the presence of Cyr61 revealed a
greater dependence on concentration. At 10 ng/ml, Cyr61 induced an
average of 64 cells to migrate per three high-powered fields
examined. At 100 ng/ml Cyr61, approximately 72 cells were found in
three fields; at 1 .mu.g/ml Cyr61, a peak of 87 cells had migrated;
at approximately 7 .mu.g/ml Cyr61, about 61 cells were observed;
and at 10 .mu.g/ml Cyr61, approximately 57 cells were found to have
migrated. The negative control revealed a constant basal level of
endothelial cell migration of 53 cells per three high-powered
microscope fields. In addition to these results, there is a perfect
correlation of the results from this in vitro assay and the results
from the in vivo cornea assay, described below.
[0171] To monitor toxicity, endothelial cells were treated with
each of the tested compounds at a range of concentrations, under
conditions identical to those used in the migration assay. Cells
were then stained with Trypan blue and cells excluding Trypan blue
were counted. The results showed that cells remained viable and
that the inhibition of migration could not be attributed to
toxicity. Where relevant, endothelial cells were pretreated for
36-48 hours with peptides at 20 .mu.M in DME with 0.1% BSA before
use in the migration assays. Toxicity was also tested over these
time frames and found to be negligible.
[0172] The ability of Cyr61 to induce matrix invasion and tube
formation by HUVE cells, as well as the ability of Cyr61 to induce
human microvascular endothelial cells to migrate, demonstrates the
angiogenic properties of this protein. It is anticipated that other
members of the ECM signaling molecule family of cysteine-rich
proteins, such as Fisp12 and CTGF, have similar properties that may
be used in methods of the invention for screening for, and
modulating, angiogenic conditions. In particular, one of ordinary
skill in the art understands that an in vitro assay for angiogenic
inhibitors involves the assay described above, including an
effective amount of Cyr61, with and without the candidate
inhibitor.
EXAMPLE 16
Migration of Endothelial Cells--An In Vitro Assay For Angiogenesis
Inhibitors
[0173] The inclusion of an effective amount of an ECM signaling
molecule, such as Cyr61, in the in vitro migration (i.e.,
chemotaxis) assay described in the preceding Example, provides an
assay designed to detect inhibitors of ECM signaling molecules and
angiogenesis. Because of the crucial role of neovascularization in
such processes as solid tumor growth and metastasis, the
development of assays to detect compounds that might antagonize
these processes would be useful.
[0174] The above-described in vitro migration assay was adapted to
include an ECM signaling molecule, Cyr61. Cyr61 was included at 1
.mu.g/ml, which was found to be the optimal dosage in titration
studies. As in the preceding Example, human microvascular
endothelial cells (Clonetics) were used. In one series of assays,
several carbohydrates and carbohydrate derivatives were analyzed.
These compounds included 10 mM mannose, 10 mM mannose-6-phosphate,
and 10 mM galactose. Results of these assays showed that Cyr61 plus
mannose yielded approximately 73 cells per set of three
high-powered microscope fields (see above). Cyr61 plus galactose
induced the migration of approximately 74 cells per set of three
high-powered fields. However, Cyr61 plus mannose-6-phosphate
yielded approximately 2 migrating cells for each set of three
high-powered fields examined. Control experiments demonstrate that
the inhibition of Cyr61 activity by mannose-6-phosphate is
specific.
[0175] The angiogenic activity of basic FGF (10 ng/ml) was also
tested, as described above, with and without mannose-6-phosphate.
In the presence of 10 mM mannose-6-phosphate, bFGF induced 51 cells
per set of three high-powered fields to migrate; in its absence,
bFGF induced the migration of approximately 52 cells. However, when
either Cyr61 or Insulin Growth Factor II (IGF-II) were tested,
mannose-6-phosphate reduced the number of migrating cells from
approximately 48 or 47 cells, respectively, to approximately 12 or
11 cells, respectively. The effect of mannose-6-phosphate on IGF II
activity was anticipated because mannose-6-phosphate is known to
compete with IGF II for their common receptor (the IGF II
receptor). Thus, mannose-6-phosphate specifically inhibits the
chemotactic activity of Cyr61 on human endothelial cells. Moreover,
because there is an essentially perfect correlation between the in
vitro migration assay and the in vivo angiogenesis assay, described
below, mannose-6-phosphate has been identified as an inhibitor of
angiogenesis based on the results of the assay disclosed herein.
Accordingly, the invention contemplates a method of inhibiting
angiogenesis comprising the step of administering an inhibitor the
angiogenic activity of Cyr61 such as mannose-6-phosphate. Assays
such as that described above may also be used to screen for other
inhibitors of angiogenesis which may be useful in the treatment of
diseases associated with angiogenesis such as cancer, and diseases
of the eye which are accompanied by neovascularization.
[0176] In an embodiment of the invention, a method of screening for
modulators of angiogenesis involves a comparative assay. One set of
conditions involves exposure of cells to a combination of Cyr61 and
a suspected modulator of cell migration. As a control, a parallel
assay is performed that exposes cells to Cyr61 alone. A promoter of
cell migration elevates the rate of in vitro cell migration
relative to the rate of migration in the presence of Cyr61 alone;
the converse is true for an inhibitor of the chemoattracting
ability of Cyr61.
EXAMPLE 17
Migration of Endothelial Cells--An In Vivo Assay
[0177] An in wivo assay for endothelial cell migration has also
been developed. In general, the assay protocol is consistent with
the disclosure of Tolsma et al., 1993. To assess angiogenesis
associated with the formation of granulation tissue (i.e., the
newly formed, proliferative, fibroblastic dermal tissue around
wounds during healing), sponge implants were used as previously
described (Fajardo, et al., Lab. Invest. 58:718-724 [1988]).
Polyvinyl-alcohol foam discs (10-mm diam.times.1-mm thick) were
prepared by first removing a 2-mm diameter central core of sponge.
PBS or an RGDS peptide (other possible test compounds include
fragments of Cyr61, RGDS peptide, small molecules such as
mannose-6-phosphate) at 100 .mu.M were added to the sponge core
which was then coated with 5 .mu.l of sterile Hydron (Interferon
Sciences, New Brunswick, N.J.). After solidifying, the coated core
was returned to the center of the sponge which was then covered on
both sides with 5 .mu.m filters and secured in place with glue
(Millipore Corp., Bedford, Mass.). One control and one test disc
were then implanted subcutaneously in the lower abdomen of
anesthetized Balb/c female mice where granulation tissue could
invade the free perimeter of the disc. Wounds were closed with
autoclips and animals left undisturbed until sacrificed.
[0178] Quantitative estimates of thymidine incorporation in situ
into endothelial cells in the discs were obtained as previously
described (Polverini. et al., J. Immunol. 118:529-532 [1977]).
Sponge implants were evaluated at days 5, 7, 10, and 14 after
implantation. Thirty minutes before sacrifice, mice were injected
with a solution containing [.sup.3H]-thymidine in saline (specific
activity 6.7 Ci/mM; New England Nuclear/Du Pont, Wilmington, Del.)
to a level of 1 .mu.Ci per gram of body weight. Sponges were
removed and facially embedded to provide a uniform section of the
entire circumference. Tissues were fixed in 10% neutral buffered
formalin, dehydrated through a graded series of alcohols, and
embedded in glycol methacrylate (Polysciences, Miles, Ill.).
Autoradiograms were prepared by dipping sections mounted on
acid-cleaned glass slides into NTB type 2 emulsion (Eastman Kodak).
After exposure for 4 weeks at 4.degree. C., autoradiographs were
developed in half strength D-19 developer, fixed in Kodak Rapid
Fixer, and stained with hematoxylin and eosin. Quantitation of
endothelial cell labeling was performed by counting all endothelial
cells that lined capillaries and venules extending from the
periphery to the center of the sponge by rectilinear scanning under
oil immersion (.times.1,000). A total of 500-700 endothelial cells
were counted in each of two sponges containing either PBS, TSP, or
peptide fragments (i.e., thrombospondin fragments). Cells were
considered labeled if five or more grains were detected over the
nucleus. The percentage of labeled cells was calculated and a
chi-square analysis of data derived from control and experimental
sponges was performed.
[0179] The results of the foregoing assay established that
thrombospondin fragments could inhibit the process of angiogenesis.
More generally, one of ordinary skill in the art would appreciate
that the scope of the present invention extends to such in vitro
assays for suspected modulators of ECM signaling molecule
activities, such as the chemotactic ability of Cyr61 to induce cell
migration. As vith other assays of the invention, a comparative
assay involves exposure of cells, in vivo, to a sponge laden with
Cyr61 in the presence or absence of a suspected modulator of Cyr61
activity. Following implantation, incubation, and removal, the
relative rates of cell migration are determined. A promoter of
Cyr61 activity will increase the rate of cell migration relative to
cell migration induced by Cyr61 alone; an inhibitor will decrease
the rate of cell migration relative to the level ascribable to
Cyr61 alone.
EXAMPLE 18
Mitogen Potentiation
[0180] In another aspect of the invention, murine Cyr61 enhanced
the mitogenic effect of growth factors on fibroblasts and
endothelial cells. When NIH 3T3 fibroblasts or HUVE cells were
treated with a non-saturating dose of either basic Fibroblast
Growth Factor (bFGF) or Platelet-Derived Growth Factor (PDGF-BB),
the addition of murine Cyr61 or human Cyr61 polypeptides (wild-type
Cyr61 and Cyr61 NT), as well as Fisp12/CTGF, significantly
increased the incorporation of radiolabeled thymidine compared to
cells treated with the growth factors alone. The thymidine
incorporation assay is a standard technique for determining whether
cells are actively glowing by assessing the extent to which the
cells have entered the S phase and are synthesizing DNA. The Cyr61
enhancement of bFGF- or PDGF-BB-induced thymidine incorporation was
dose-dependent, requiring a minimum concentration of 0.5-1.0
.mu.g/ml of recombinant protein for either cell type. Cyr61
polypeptides are expected to have analogous enhancing or
potentiating effects on the ability of other growth factors
(e.g.,PDGF-BB) to induce the mitogenesis of endothelial cells,
fibroblasts, and other mammalian cell types as measured, e.g., by
thymidine incorporation (i.e., DNA synthesis). The enhancement of
DNA synthesis by Cyr61 was inhibited by the addition of specific
anti-Cyr61 antiserum.
[0181] More specifically, NIH 3T3 fibroblast cells were plated on
24-well plates at 3.times.10.sup.4 cells/well and grown in DMEM
with 10% fetal bovine serum (Intergen Co., Purchase, N.Y.) for 3-4
days and incubated with medium containing 0.2% FBS for the
following 48 hours. The following compounds, at the parenthetically
noted final concentrations, were then added to the plated cells in
fresh DMEM containing 0.2% fbs and [.sup.3H]-thymidine (1 .mu.Ci/ml
final concentration; ICN Biomedicals, Inc., Costa Mesa, Calif.):
bFGF (15 ng/ml), PDGF-BB (30 ng/ml), and murine Cyr61 (0.5-5
.mu.g/ml). These compounds were added to individual plates
according to the following pattern: 1) no supplementation; 2)
murine Cyr61; 3) bFGF; 4) murine Cyr61 and bFGF; 5) PDGF-BB; and 6)
murine Cyr61 and PDGF. After 18-20 hours of incubation, cells were
washed with PBS and fixed with 10% trichloroacetic acid. DNA was
dissolved in 0.1 N NaOH and thymidine incorporation was determined.
The results indicated that murine Cyr61, in the absence of a growth
factor, did not stimulate DNA synthesis as measured by tritiated
thymidine incorporation. Without any supplements, 3T3 cells
incorporated approximately 1.8.times.10.sup.4 cpm of
[.sup.3H]-thymidine, in the presence or absence of Cyr61. Cells
exposed to bFGF alone incorporated about 1.2.times.10.sup.5 cpm;
cells contacting bFGF and murine Cyr61 incorporated
2.times.10.sup.5 cpm. Cells receiving PDGF-BB incorporated about
1.2.times.10.sup.5 cpm; and cells exposed to PDGF-BB and murine
Cyr61 incorporated approximately 2.4.times.10.sup.5 cpm. Therefore,
murine Cyr61 did not function as a mitogen itself, but did
potentiate the mitogenic activity of bFGF and PDGF-BB, two known
growth factors.
[0182] The ability of murine Cyr61 to potentiate the mitogenic
effect of different levels of bFGF also revealed a threshold
requirement for the growth factor. Human umbilical vein endothelial
cells were plated essentially as described above for 3T3 cells and
exposed to a constant amount of murine Cyr61; controls received no
Cyr61. Different plates were then exposed to different levels of
bFGF, comprising a series of bFGF concentrations ranging from 0-10
ng/ml. Following culture growth in the presence of
[.sup.3H]-thymidine for 72 hours, cells exposed to 0-0.1 ng/ml of
bFGF exhibited a baseline level of thymidine incorporation
(approximately 4.times.10.sup.2 cpm), in the presence or absence of
Cyr61. At 1 ng/ml bFGF, however, HUVE cells increased their
thymidine incorporation in the presence of bFGF to 6.times.10.sup.2
cpm; in the presence of 1 ng/ml bFGF and murine Cyr61, HUVE cells
incorporated 1.3.times.10.sup.3 cpm. At 10 ng/ml bFGF, cells
exposed to bFGF incorporated about 1.8.times.10.sup.3 cpm
thymidine; cells receiving 10 ng/ml bFGF and Cyr61 incorporated
approximately 6.1.times.10.sup.3 cpm.
[0183] The capacity of murine Cyr61 to potentiate the mitogenic
activity of bFGF was verified by a thymidine incorporation assay
involving HUVE cells and various combinations of bFGF, Cyr61, and
anti-Cyr61 antibodies. Cells were plated and grown as described
above. The following combinations of supplements (final plate
concentrations noted parenthetically) were then pre-incubated for 1
hour before addition to individual plates: 1) pre-immune antiserum
(3%); 2) bFGF (15 ng/ml) and pre-immune antiserum (3%); 3)
pre-immune antiserum (3%) and Cyr61 (4.mu.g/ml); 4) pre-immune
antiserum (3%), Cyr61 (4 .mu.g/ml), and bFGF (15 ng/ml); 5)
anti-Cyr61 antiserum (3%); 6) anti-Cyr61 antiserum and bFGF (15
ng/ml); 7) anti-Cyr61 antiserum (3%) and Cyr61 (4 .mu.g/ml); and 8)
anti-Cyr61 antiserum (3%), Cyr61 (4 .mu.g/ml), and bFGF (15
ng/ml).
[0184] Following incubation in the presence of [.sup.3H]-thymidine
as described above, cells exposed to pre-immune antiserum
incorporated about 2.times.10.sup.2 cpm thymidine; cells contacting
pre-immune antiserum and bFGF incorporated 1.3.times.10.sup.3 cpm;
cells receiving pre-immune antiserum and Cyr61 incorporated
1.times.10.sup.2 cpm; cells receiving pre-immune antiserum, Cyr61,
and bFGF incorporated 3.6.times.10.sup.3 cpm; cells exposed to
anti-Cyr61 antiserum incorporated 2.times.10.sup.2 cpm; cells
receiving anti-Cyr61 antiserum and bFGF incorporated about
1.3.times.10.sup.3 cpm; cells contacting anti-Cyr61 antiserum and
Cyr61 incorporated about 1.times.10.sup.2, and cells receiving
anti-Cyr61 antiserum, Cyr61, and bFGF incorporated 1.times.10.sup.3
cpm. These results indicate that pre-immune antiserum had no effect
on Cyr61-induced potentiation of bFGF mitogenic activity.
Anti-Cyr61 antiserum, however, completely abolished the
potentiation of bFGF by Cyr61. Moreover, the effect of anti-Cyr61
antiserum was specific to Cyr61-induced mitogenic potentiation
because anti-Cyr61 antiserum had no effect on the mitogenic
activity of bFGF per se. Therefore, Cyr61 can be used as a reagent
to screen for useful mitogens.
[0185] Additional antibody studies using integrin-specific
monoclonal antibodies showed that from an entire panel of specific
anti-integrin antibodies, only an antibody (LM609) specific for
integrin .alpha..sub.V.beta..sub.3 inhibited the induction of DNA
synthesis by Cyr61 polypeptides, including wild-type Cyr61 and
Cyr61 NT. Thus, integrin .alpha..sub.V.beta..sub.3 is required for
Cyr61-induced mitogenesis, although it is not involved in
fibroblast adhesion (see Example 19).
[0186] DNA synthesis for HUVE cells and NIH 3T3 fibroblasts was
measured by thymidine incorporation as described previously
(Kireeva et al., [1996]) with minor modifications. HUVE cells were
grown in 24-well plates to a subconfluent state, serum-starved for
24 hours and treated with F12K medium containing 10% fetal bovine
serum (FBS), 1 .mu.Ci/ml [.sup.3H]-thymidine and 10 ng/ml basic
Fibroblast Growth Factor (bFGF) (Gibco-BRL, Inc.) with various
concentrations of Cyr61 and Fisp12 as indicated. NIH 3T3
fibroblasts were grown to subconlfluence, serum-starved for 48
hours, and treated with Minimal Essential Medium (MEM) containing
0.5% FBS, 1 .mu.Ci/ml [.sup.3H]-thymidine, bFGF and various
concentrations of Cyr61 or Fisp12. Thymidine incorporation into the
trichloroacetic acid-insoluble fraction was determined after 24
hour incubation. Logarithmically grown mink lung epithelial cells
(Mv1lu, CCL64) were treated with various concentrations of
TGF-.beta.1 (Gibco-BRL) and 2 .mu.g/ml of Cyr61 or Fisp12 for 18
hours; [.sup.3H]-thymidine was then added to 1 .mu.Ci/ml for 2
hours. Thymidine incorporation was determnined as described
above.
[0187] Purified recombinant Fisp12 protein did not exhibit any
mitogenic activity under any tested assay conditions. Rather,
Fisp12 was able to enhance DNA synthesis induced by fibroblast
growth factor in either NIH 3T3 fibroblasts or HUVE-cells. This
activity was nearly indistinguishable from that exhibited by
Cyr61.
[0188] Whereas in fibroblasts and endothelial cells, Cyr61 and
Fisp12 enhance growth factor-induced DNA synthesis, both proteins
can also enhance growth factor-mediated actions in another way. It
is known that TGF-.beta. acts to inhibit DNA synthesis in
epithelial cells (Satterwhite et al., 1994). It was observed that
both Cyr61 and Fisp12 enhanced the ability of TGF-.beta. to inhibit
DNA synthesis in mink lung epithelial cells. The data demonstrate
that both recombinant Cyr61 and Fisp12, purified from serum-free
sources, are not mitogenic by themselves, but have the ability to
synergize with the actions of polypeptide growth factors. Cyr61 and
Fisp12 enhance DNA synthesis induction by FGF, and enhance DNA
synthesis inhibition by TGF-.beta..
[0189] Beyond the use of Cyr61 polypeptides and Fisp12, the present
invention comprehends the use of CTGF in methods to potentiate the
mitogenic effect of true growth factors, or to screen for true
growth factors. Those contemplated uses are in contrast to the
reported use of CTGF as a mitogen or growth factor itself. U.S.
Pat. No. 5.408,040, column 7, line 65, to column 11, line 7,
incorporated herein by reference hereinabove. It is expected that,
in addition to murine and human Cyr61 polypeptides, Fisp12, and
CTGF, other ECM signaling molecules, such as members of the CCN
family of proteins, will function to potentiate the mitogenic
activity of true growth factors and will not function as true
growth factors themselves.
[0190] Further, the invention comprehends methods of screening for
modulators of mitogen potentiation. A comparative assay exposes
subconfluent cells to an ECM signaling molecule such as Cyr61, a
growth factor, and a suspected modulator of an ECM signaling
molecule. As a control, similar cells are exposed to the ECM
signaling molecule and the growth factor. A further control exposes
similar cells to the growth factor and the suspected modulator in
the absence of the ECM signaling molecule. Based on the relative
cell proliferation rates, as measured by, e.g., [.sup.3H]-thymidine
incorporation, an identification of a suspected modulator as a
promoter of mitogen potentiation (elevated cell proliferation in
the presence of all three molecules) or an inhibitor of mitogen
potentiation (decreased cell proliferation in the presence of the
three molecules) can be made.
[0191] Additionally, the invention comprehends the use of ECM
signaling molecules such as Cyr61 polypeptides in methods for
treating conditions or disorders, such as diseases, associated with
an under- or over-proliferation of mammalian cells. One of ordinary
skill would readily comprehend that Cyr61 polypeptides having
growth-factor-enhancing activity are suitable for treating
conditions characterized by an undesirably low rate of cell
proliferation. The use of Cyr61 polypeptides lacking such an
activity could be used to treat conditions characterized by an
over-proliferation of cells. Any means known in the art for
delivering the therapeutic polypeptides or modulators is suitable,
including direct injection into a mammal, such as a human, using
any known route (e.g., subcutaneous, intramuscular, intravenous,
intraperitoneal), optionally in the presence of a known adjuvant,
excipient, carrier, or vehicle such as a liposome, or by gene
therapy using any conventional nucleic acid delivery system. Any of
these delivery mechanisms may be modified to target delivery of the
therapeutic by mechanisms known in the art (e.g., association with
a targeting molecule such as an antibody recognizing a desired cell
type).
EXAMPLE 19
Cornea Assay For Angiogenic Factors And Modulators
[0192] Another assay for modulators of angiogenesis is an in vivo
assay for assessing the effect of a suspected modulator in the
presence of an ECM signaling molecule-related biomaterial, such as
Cyr61, on angiogenesis is the Cornea Assay. The Cornea Assay takes
advantage of the absence of blood vessels in the cornea, which in
the presence of an angiogenic factor, results in the detectable
development of capillaries extending from the sclera into the
cornea. Friedlander et al., Science 270:1500-1502 (1995). This
ingrowth of new blood vessels from the sclera can be
microscopically monitored. Further, the visually determined rate of
migration can be used to assess changes in the rate of
angiogenesis. These cornea assays may be performed using a wide
variety of animal models. Preferably, the cornea assays are
performed using rats. By way of example, an assay for suspected
modulators of Cyr61 using this assay is disclosed. To perform this
assay, Cyr61 is initially titrated using primary capillary
endothelial cells to determine effective concentrations of Cyr61.
Subsequently, Cyr61, in the presence or absence of a suspected
modulator, is surgically implanted into the corneas of mammalian
laboratory animals, e.g., rabbits or rats. In a preferred
embodiment, Cyr61 (or Cyr61 and a suspected modulator) is embedded
in a biocompatible matrix, using matrix materials and techniques
that are standard in the art. Subsequently, eyes containing
implants are visually observed for growth of the readily visible
blood vessels within the eye. Control implantations may consist of
physiologically balanced buffers embedded in the same type of
matrix and implanted into eyes of the same type of laboratory
animal receiving the Cyr61-containing implants.
[0193] The development of an in vivo cornea assay for angiogenic
factors has advantages over existing in vitro assays for these
factors. The process of angiogenesis involves four distinct phases:
induction of vascular discontinuity, endothelial cell movement,
endothelial cell proliferation, and three-dimensional restructuring
and sprouting. In vitro assays can evaluate only two of these
steps: endothelial cell migration and mitogenesis. Thus, to provide
a comprehensive assay for angiogenic factors, an in vivo assay such
as the cornea assay is preferred.
[0194] The cornea assay has been used to confirm the effect of
angiogenic factors such as Cyr61, Fisp12, CTGF, and Nov, on the
process of angiogenesis. Moreover, modifying the cornea assay by
including any of these angiogenic factors and a suspected modulator
of their activity results in a cornea assay for modulators of
angiogenesis. For example, in one embodiment of the invention, dose
of an angiogenic factor such as Cyr61 could be used in cornea
assays for positive effectors of the angiogenic activity of Cyr61.
An appropriate dose of Cyr61 would initially be determined by
titration of the dose response relationship of Cyr61 with
angiogenic events. Inclusion of a control assay lacking Cyr61 would
eliminate compounds having a direct effect on angiogenesis. In an
alternative embodiment of the invention, an effective dose of an
angiogenic factor such as Cyr61 could be used to assay for negative
modulators of the activity of an angiogenic factor. In yet another
alternative embodiment, a corneal implant comprises Cyr61 and
another corneal implant comprises Cyr61 and a suspected modulator
of angiogenesis. Measurements of the development of blood vessels
in the implanted corneas provides a basis for identifying a
suspected modulator as a promoter of angiogenesis (elevated blood
vessel development in the cornea containing an implant comprising
the suspected modulator. A relative decrease in blood vessel
development identifies an inhibitor of angiogenesis.
[0195] The rat is preferred as the animal model for the cornea
assay. Disclosures in the art have established the rat model as a
well-characterized system for analyzing angiogenesis. Parameters
such as implant size, protein release dynamics, and suitable
surgical techniques, have been well characterized. Although any
strain of rat can be used in the cornea assay, preferred strains
will be well-characterized laboratory strains such as the
Sprague-Dawley strain.
[0196] Although rats of various sizes can be used in the cornea
assay, a preferred size for the rats is 150-200 g/animal.
Anesthesia is induced with Methoxyflurane and is maintained for
40-60 minutes with sodium pentobarbital (50 mg/kg, delivered
intraperitoneally). The eyes are gently opened and secured in place
by clamping the upper eyelid with a non-traumatic hemostat. Two
drops of sterile proparacaine hydrochloride (0.5%) are then placed
on each eye as to effect local anesthesia. Using a suitable
surgical blade such as a No. 11 Bard Parker blade, an approximately
1.5 mm incision is made approximately 1 mm from the center of the
cornea. The incision extends into the stromna but not through it. A
curved iris spatula approximately 1.5 mm in width and approximately
5 mm in length is then inserted under the lip of the incision and
gently blunt-dissected through the stroma toward the outer canthus
of the eye. Slight finger pressure against the globe of the eye
helps to steady the eye during dissection. The spatula penetrates
the stroma no more than approximately 2.5 mm. Once the cornea
pocket is made, the spatula is removed and the distance between the
limbus and base of the pocket is measured to make sure the
separation is at least about 1 mm.
[0197] To provide slow release of the protein after implantation in
the cornea, protein is mixed with poly-2-hydroxyethylmethacrylate
(Hydron.RTM.), or an equivalent agent, to form a pellet of
approximately 5 .mu.l. Implants made in this way are rehydrated
with a drop of sterile lactated Ringers solution and implanted as
described above. After implantation, the corneal pocket is sealed
with erythromycin ointment. After implantation, the protein-Hydron
pellet should remain near the limbus of the cornea (cornea-sclera
border) and vision should not be significantly impaired.
[0198] Following surgery, animals are examined daily for seven days
with the aid of a stereomicroscope to check for inflammation and
responses. To facilitate examination, the animal is anesthetized
with Methoxyflurane and the anesthetic is continuously administered
by nose cone during examination. During this seven day period,
animals are monitored for implant position and corneal exudate.
Animals exhibiting corneal exudate are sacrificed. A preferred
method of euthanasia is exsanguination. Animals are initially
anesthetized with sodium pentobarbital (50 mg/kg) and then
perfused, as described below.
[0199] After seven days, animals are perfused with colloidal carbon
(e.g.,India Ink). Anesthesia is induced with Methoxyflurane, and is
maintained with sodium pentobarbital (50 mg/kg, intraperitoneally).
Each animal is perfused with 100-200 ml warm (37.degree. C.)
lactated Ringers solution per 150 g of body mass via the abdominal
aorta. Once the snout of the animal is completely blanched, 20-25
ml of colloidal carbon is injected in the same way as the Ringers
solution, until the head and thoracic organs are completely black.
Eyes are then enucleated and fixed. Corneas are excised, flattened,
and photographed.
[0200] Each protein is typically tested in three doses, in
accordance with the practice in the art. Those of ordinary skill in
the art realize that six positive corneal responses per dose are
required to support an identification of an angiogenic response. An
exemplary cornea assay includes three doses of the protein under
study, with six rats being tested at each dose. Additionally, six
animals are exposed to a buffer-Hydron implant and serve as
negative controls. Exposure of at least three animals to a known
angiogenic factor-Hydron implant serve as positive controls.
Finally, to demonstrate the specificity of any observed. response,
six animals are exposed to implants containing a single dose of the
protein under study, an excess of neutralizing antibody, and
Hydron.
[0201] A cornea assay as described above was performed to assess
the ability of Cyr61 to induce angiogenesis. Four animals were
given negative control implants containing a buffer-Hydron pellet
(both eyes). Each of these animals failed to show any blood vessel
development in either eye after seven days. Six animals received
implants containing a biologically effective amount of Fibroblast
Growth Factor (0.15 .mu.M) in one eye and a control pellet in the
other eye; all six showed angiogenic development in the eye
receiving FGF, none showed neovascularization in the eye receiving
the negative control. Seven animals received 1 .mu.g/ml Cyr61, in
one eye and all seven of these eyes showed blood vessel growth; one
of the seven eyes receiving a negative control showed angiogenic
development. Finally, four animals received implants locally
releasing 1 .mu.g/ml Cyr61 (Hydron prepared with a 10 .mu.g/ml
Cyr61 solution) and a specific anti-Cyr61 antibody in three-fold
excess over Cyr61; none of the eyes of this group showed any
angiogenic development. Thus, the in vivo assay for angiogenesis
identifies angiogenic factors such as FGF and Cyr61. The assay also
is able to reveal inhibition of angiogenic development induced ECM
signaling molecules such as Cyr61.
EXAMPLE 20
Blood Clotting
[0202] ECM signaling molecules are also useful in correcting
hemostasis, or abnormal blood clotting. A defect in blood clotting
caused by, e.g., low level expression of cyr61 which thereby allows
Tissue Factor Pathway Inhibitor (TFPI) to act unchecked can be
corrected by expression or use of recombinant Cyr61 protein.
[0203] Cyr61 can interact with TFPI, a protein that inhibits
extrinsic blood coagulation. TFPI inhibits blood clotting in a two
step process. First, TFPI binds to factor Xa and the TFPI:Xa
complex then interacts with the Tissue Factor (TF):Factor VIIa
complex, thereby inhibiting the latter complex. The TF:Factor VIIa
complex is the complex that activates factors IX and X. By
inhibiting TF:VIIa, TFPI reg,ulates coagulation by preventing the
activation of Factors IX and X, required for blood clotting. The
interaction of Cyr61 with TFPI inhibits the activity of TFPI, thus
promoting blood coagulation. Cyr61 is, thus, a tissue factor
agonist.
[0204] Because of the interaction of Cyr61 and TFPI, Cyr61 can
control the ability of TFPI to inhibit coagulation, thereby
regulating hemostasis. A defect in Cyr61 may lead to the inability
to inhibit TFPI at the appropriate time, resulting in excessive
inhibition of tissue factor, thereby preventing clot formation.
Deregulated expression of Cyr61 will conversely inhibit the
activity of TFPI constitutively, and thus tissue factor is
constantly active, resulting in excessive clotting. When the
expression of cyr61 in endothelial cells is deregulated, one
possible outcome is thrombosis.
[0205] In addition to Cyr61, other ECM signaling molecules, such as
Fisp12 and CTGF, have been shown to exert effects on cells
participating in angiogenesis. Consequently, it is anticipated that
a variety of ECM signaling molecule-related biomaterials, alone or
in combination, may be used in the methods of the invention
directed towards modulating hemostasis.
EXAMPLE 21
Ex vivo Hematopoietic Stem Cell Cultures
[0206] To investigate the effect of Cyr61 on the growth of
primitive multipotent stein cells, several assays that distinguish
these cells from more mature progenitor cells in a hematopoietic
culture are employed. These assays make use of physicochemical
(fibronectin-biniding) or growth and development-related
(generation of progenitor blast colonies) differences between
immature and mature subsets of cells.
[0207] Two cell lines which require conditioned media for growth
are used as a source of hematopoietic stem cells (HSC). These
cloned, factor-dependent mIiiurine lines are B6Sut (cloned from
long term bone marrow culture and capable of growing in liquid
medium without differentiation, but multipotent in agar, as
described in Greenberger et al., Proc. Natl. Acad. Sci.
[USA]80:2931 [1983]), and FDCP-mix (cloned from long term bone
marrow culture cells infected with the recombinant virus
src-MoMuLV, and are multipotent in agar cultures, as described in
Spooncer et al., Nature 310:2288 [1984]). B6Sut cells are
propagated in Kincaid's medium with 10% fetal calf serum (FCS) and
10% 6.times.-concentrated WEHI-conditioned medium. Greenberger et
al. FDCP-mix cells are propagated in Fischer's medium with 20%
horse serum and 10% 6.times.-concentrated WEHI-conditioned medium.
The cell lines are propagated at 37.degree. C., 5% CO.sub.2.
[0208] Various ex vivo or in vitro cultures are assayed for
population growth in the presence or absence of exogenously
supplied murine Cyr61 or polyclonal anti-Cyr61 antibodies. Under
limiting dilution conditions, the cobblestone area forming cell
(CAFC) assay is used to identify cells with long term repopulating
ability. Ploemacher et al., Blood 74:2755 (1989); Ploemacher et
al., Blood 78:2527 (1991). Cells identified as having long term
repopulating ability by the CAFC assay are then analyzed by
measuring three parameters: Rate of population doubling, mitotic
index, and rate of DNA synthesis.
[0209] Long term cultures, with or without supplementation with
Cyr61, are assayed for their levels of primitive HSC in the CAFC
assay. van der Sluijs et al., Exp. Hematol. 22:1236 (1994). For
example, M2-10 B4 stromal cells provide a stromal cell layer for
either B6Sut or FDCP-mix, which are each subjected to the CAFC
assay in the following manner. Stromal cell layers are prepared by
inoculating 5.times.10.sup.5 M2-10B4stromal cells (a cell line
cloned from bone marrow stroma. Sutherland et al., Blood 78:666
[1991]) into each well of a 96-well culture plate in DMEM with 10%
FCS. When the cells approach confluency, they are rinsed with PBS
and irradiated (20 Gy of gamma-irradiation, 1.02-1.04 Gy/minute) to
prevent replication of any hematopoietic cells within the stroma,
without affecting the stroma's ability to support
hematopoiesis.
[0210] B6Sut or FDCP-mix cells (sources of HSC) are added to the
irradiated stromal cells in DMEM with 10% FCS, in the presence or
absence of Cyr61 (10 .mu.g/ml final concentration). After
overlaying B6Sut or FDCP-mix on the stromal cells, the cultures are
incubated (e.g., 28-35 days for the murine system) and the number
of cobblestone-forming areas (which identifies cells with long-term
repopulating ability) are counted to determine the HSC
frequency.
[0211] In a variation of the above-described CAFC assay, cells
(e.g., B6Sut or FDCP-mix) are initially maintained in parallel
cultures in the presence or absence of a Cyr61 polypeptide.
Subsequently, CAFC assays are performed, as generally described
above; however, the assay is preferably performed in the complete
absence of CAFC. It is expected that cells cultured in the presence
of Cyr61 polypeptides will exhibit an increase in the frequency of
HSC relative to cells initially cultured in the absence of Cyr61
polypeptides.
[0212] Following identification of cells with long-term
repopulating ability, population doubling rates are determined,
e.g., by microscopic examination of cell morphology to determine
the numbers of long term repopulating cells (and more mature short
term progenitor cells) present in the various experimental long
term cultures. Subsequent investigation of the expansion and
differentiation capacities of the potential long term HSC cultures
is used for confirmation of suitable candidate cell lines.
[0213] The mitotic index is determined according to procedures
standard in the art. Keram et al., Cancer Genet. Cytogenet. 55:235
(1991). Harvested cells are fixed in methanol:acetic acid (3:1,
v:v), counted, and resuspended at 10.sup.6 cells/ml in fixative.
Ten microliters of this suspension is placed on a slide, dried, and
treated with Giemsa stain. The cells in metaphase are counted under
a light microscope, and the mitotic index is calculated by dividing
the number of metaphase cells by the total number of cells on the
slide. Statistical analysis of comparisons of mitotic indices is
performed using the 2-sided paired t-test.
[0214] The rate of DNA synthesis is measured using a thymidine
incorporation assay. Various cultures are propagated in 1 .mu.Ci/ml
[.sup.3H]-thymidine (ICN Biomedicals, Inc., Costa Mesa, Calif.) for
24-72 hours. Harvested cells are then rinsed with PBS and fixed
with 10% trichloroacetic acid. DNA is dissolved in 0.1 N NaOH, and
thymidine incorporation is determined, for example by liquid
scintillation spectrophotometry.
[0215] The function of Cyr61 polypeptides in promoting the
maintenance and/or expansion of long-term hematopoietic stem cell
cultures was confirmed by antibody studies. Having determined that
Cyr61 is a stroma-associated component important for the
maintenance/expansion of long-term HSC cultures, stromal-contact
bone marrow cell cultures were exposed to Cyr61 polypeptides in the
presence or absence of anti-Cyr61 antibodies. Those cultures in
which the Cyr61 activity had been neutralized by exposure to
anti-Cyr61 antibodies showed a decrease in vitality of the culture,
an increase in the number of visually detectable differentiated
hematopoietic cells in the culture, and a decrease in the cell
fraction comprising HSC, and a concomitant increase in the cell
fraction comprised of committed cells, relative to HSC cultures
maintained in the presence of Cyr61, but the absence of anti-Cyr61
antibodies. Consequently, the activity of Cyr61 polypeptides is
expected to be important for the stromal-dependent expansion of
undifferentiated hematopoietic stem cells.
[0216] The use of an ECM signaling molecule-related biomaterial,
such as Cyr61, can be used in the ex vivo expansion of
hematopoietic stem cell cultures. In addition, more than one ECM
signaling molecule-related biomaterial may be used to expand these
cultures. For example, Cyr61, with its expression targeted locally,
may be combined with Fisp12, which is secreted and, consequently,
exhibits a more expansive targeting. As an alternative, CTGF may be
substituted for Fisp12, its mouse ortholog. One of skill in the art
would be able to devise other combinations of ECM signaling
molecule-related biomolecules that are within the spirit of the
invention.
[0217] Those of ordinary skill in the art will recognize that the
successful expansion of hematopoietic stem cell cultures in the
presence of ECM signaling molecules such as Cyr61 polypeptides
provides a basis for a method of screening for suspected modulators
of that expansion process. As in the other methods of the
invention, a suspected modulator is combined with an ECM signaling
molecule such as Cyr61 and exposed to primitive cells. In parallel,
the ECM signaling molecule is exposed to similar cells. The
relative rates of expansion may be used to identify a promoter, or
inhibitor, of the ability of the ECM signaling molecule to expand
pluripotent hematopoietic stem cell cultures.
[0218] Cyr61, alone or in combination with other hematopoietic
growth factors, may also be used to expand stem cell populations
taken from a patient and which may, after expansion, be returned to
the patient or other suitable recipient patient after for example,
chemotherapy or other treatment modalities that result in the
depletion of blood cells in a patient. Stem cell populations
expanded according to the present invention may also be used in
bone marrow transplants in a patient in need thereof. Further, the
invention contemplates the delivery of an ECM signaling molecule
such as a Cyr61 polypeptide (including polypeptide fragments that
inhibit endogenous Cyr61 activity) to a subject (e.g., patient)
that would benefit from increased, or decreased, HSC production or
hematopoiesis, using delivery means known in the art.
EXAMPLE 22
Organ Regeneration
[0219] The role of Cyr61 in the various cellular processes invoked
by changes in the cellular growth state indicate that this protein
would be effective in promoting organ regeneration. Towards that
end, studies were conducted to determine the expression profile of
murine cyr61 in remaining liver tissue following a partial
hepatectomy. (The response of remaining liver tissue following
partial hepatectomy is a model for the liver's response to a
variety of injuries, including chemical injuries, e.g., exposure to
toxic levels of carbon tetrachloride.)
[0220] BALB/c 3T3 (Charles River) mice were subjected to partial
hepatectomies removing approximately 67% of their liver tissue.
Higgins et al., Archs. Path. 12:186-202 (1931). Twenty microgram
aliquots of RNA were removed from the remaining liver tissue at
varying times following the operation and liver RNA was isolated by
tissue homogenization followed by guanidinium isothiocyanate,
cesium chloride precipitation. Sambrook et al. RNAs were then
immobilized on nitrocellulose filters and probed with radiolabeled
clones containing various regions of murine cyr61 cDNA. Results
were visualized by aultoradiography and indicated that removal of
liver tissue induced cyr61 mRNA expression, particularly in cells
found near the injury site. Consequently, induction of cyr61
expression, e.g., by recombinant techniques, might promote the
regeneration of organs such as liver. For example, cyr61 expression
can be controlled, e.g., by introducing recombinant cyr61
constructs that have been engineered to provide the capacity to
control expression of the gene, e.g., by the use of tissue-specific
promoters, e.g., the K14 promoter for expression in skin. The
recombinant cyr61 may be introduced to cells of the relevant organ
by gene therapy techniques using vectors that facilitate
homnologous recombination (e.g., vectors derived from
Herpesviruses. Adenovirus, Adeno-associated Virus, Cytomegalovirus,
Baculovirus, retroviruses, Vaccinia Virus, and others). Techniques
for introducing heterologous genes into eukaryotic cells, and
techniques for integrating heterologous genes into host chromosomes
by homologous recombination, are well known in the art.
[0221] The development of skin, another organ, is also affected by
Cyr61. The expression of cyr61 is induced in cells in the vicinity
of skin injuries. Also, as described above, Cyr61 has a chemotactic
effect (i.e., Cyr61 induces cell migration) on endothelial cells
and fibroblasts. Further, Cyr61 induces the proliferation of
endothelial cells and fibroblasts. Both processes are involved in
the healing of skin wounds. Accordingly, Cyr61 administration,
e.g., by localized or topical delivery, should promote skin
regeneration.
[0222] Cyr61 is also highly expressed in lung epithelium. These
cells are frequently injured by exposure to environmental
contaminants. In particular, lung epithelium is frequently damaged
by air-borne oxidants. The administration of Cyr61, e.g., in
atomizers or inhalers, may contribute to the healing of lung
epithelium damaged, e.g., by environmental contaminants.
EXAMPLE 23
Chondrogenesis--ECM Signaling Molecules Are Expressed in
Mesenchyme
[0223] Some ECM signaling molecules are also expressed in cells,
such as mesenchyme cells, that ultimately become a part of the
skeletal system. In this Example, Cyr61 is identified as one of the
ECM signaling molecules expressed in mesenchyme cells. Limb
mesenchymal cells were grown in micromass culture as described
above on glass coverslips (Fisher) for 3 days. Cultures were fixed
in 4% paraformaldehyde in PBS, incubated for 30 minutes at room
temperature with 1 mg/ml bovine testicular hyaluronidase (type IV,
Sigma) in 0.1 N sodium acetate (pH 5.5) with protease inhibitors
phenymethylsulfonyl fluoride (PMSF, 1 mM), pepstatin (1 .mu.g/ml),
leupeptin (1 .mu.g/ml), aprotinin (1 .mu.g/ml), aminocaproic acid
(50 mM), benzamidine (5 mM), and EDTA (1 mM), blocked with 10% goat
serum in PBS and incubated overnight at 4.degree. C. with primary
antibodies against Cyr61 (Yang et al., [1991]), fibronectin (Gibco)
and tenascin (Gibco). Controls were incubated with anti-Cyr61
antibodies neutralized with 1 .mu.g/ml purified Cyr61. Cultures
were subsequently incubated with FITC-conjugated goat-anti-rabbit
secondary antibody (Zymed), for 1 hour at room temperature.
[0224] For whole mount immunohistochemical staining, mouse embryos
from gestational days 10.5 to 12.5 were fixed in 4%
paraformaldehyde in PBS, dehydrated in methanol/PBS and stored at
-20.degree. C. in absolute methanol. After rehydration, embryos
were incubated with anti-Cyr61 antibodies as described in Hogan et
al, Development 120:53-60 (1994), incorporated herein by reference.
Controls were incubated with anti-Cyr61 antibodies neutralized with
1 .mu.g/ml purified Cyr61. Immunostained embryos were fixed,
cleared and photographed.
[0225] Consistent with the transient expression of the cyr61 mRNA
in somitic mesenchymal cells that are differentiating into
chondrocytes (O'Brien et al., [1992]), the Cyr61 protein was found
in the developing embryonic skeletal system. Cyr61 was localized by
whole mount immunohistochemical staining to the proximal limb bud
mesenchyme in gestational day 10.5 to 12.5 embryos. The Cyr61
protein was localized to the developing vertebrae, the calvarial
frontal bone and the first brachial arch, as well as in the heart
and umbilical vessels, forming an expression pattern that was
consistent with the cyr61 mRNA expression pattern (O'Brien el al.,
[1992]).
[0226] Cyr61 protein could be detected by immunoblot analysis in
whole limb buds and in micromass cultures of limb bud mesenchymal
cells. The level of Cyr61 protein remained at relatively constant
levels throughout the 4 day culture period during which
chondrogenesis occurred. Using quantitative immunoblot analysis,
Cyr61 was estimated to represent approximately 0.03% of total
cellular and extracellular proteins in the mesenchymal cell
cultures. Cyr61, tenascin (Gibco), and fibronectin were localized
to the cartilage nodules by immunofluorescent staining in the
mesenchymal cell cultures. Cyr61 and tenascin were primarily
localized among the intranodular cells, while a fibrillar staining
pattern was also observed around and between the cartilage nodules
with anti-fibronectin antibodies. A similar immunofluorescent
staining pattern was observed in transverse sections of the
micromass cultures for all three antibodies. Together, these
results show that endogenous Cyr61 is localized in the developing
limb bud mesenchyme, both in vivo and in vivo.
EXAMPLE 24
Chondrogenesis--ECM Signaling Molecules Promote Cell Adhesion
[0227] Cyr61 is a secreted protein that mediates the adhesion of
fibroblasts and endothelial cells to non-tissue culture-treated
plastic surfaces (Kireeva et al., [1996]). The attachment of limb
bud mesenchymal cells on non-tissue culture dishes coated with BSA,
Cyr61, tenascin, and fibronectin, were compared.
[0228] Cyr61, fibronectin (Gibco), or tenascin (Gibco) were diluted
in 0.1% protease-free bovine serum albumin (BSA) in PBS with 0.5 mM
PMSF, to a final concentrations of 10 or 50 .mu.g/ml. A 10 .mu.l
drop/well was placed in a non-tissue culture treated 24-well plate
(Corning), and incubated at room temperature for 2 hours. The wells
were blocked with 1% BSA in PBS for 1 hour at room temperature, and
rinsed with serum-free MEM (Modified Eagle's Medium). Limb
mesenchymal cells, suspended at 5.times.10.sup.5 cell/ml in
serum-free MEM, were added at a volume of 400 .mu.l/well, and
incubated at 37.degree. C., 5% CO.sub.2 for 1 or 3 hours. At each
time point, the cell suspension was removed, the wells were rinsed
with MEM and the remaining adherent cells were photographed.
[0229] Cells attached poorly to BSA-coated dishes, but adhered as
clusters of rounded cells to Cyr61- and tenascin-coated dishes
within 1 hour of plating. In contrast, cells plated on
fibronectin-coated dishes attached uniformly and started to spread.
When cells were allowed to attach for 3 hours, many more adherent
cells were observed. Furthermore, intercellular clustering and
rounded cell morphology were maintained in cells plated on Cyr61
and tenascin, while cells plated on fibronectin spread to form a
monolayer. These observations show that Cyr61 mediates the adhesion
and maintenance of a rounded cellular morphology which is conducive
for mesenchymal cell chondrogenesis (Zanetti et al., Dev. Biol.
139:383-395 [1990]; Solursh et al., Dev. Biol. 94:259-264 [1982]),
similar to that previously reported for tenascin (Mackie et al., J.
Cell Biol. 105:2569-2579 [1987]).
[0230] As mentioned previously, ECM signaling molecules such as
Cyr61 may be used in methods of screening for modulators of cell
adhesion, including, but not limited to, the adhesion of
chondrocytes. The comparative assay, described above, measures the
relative adhesion levels of cells exposed to a combination of an
ECM signaling molecule and a suspected modulator of cell adhesion
and cells exposed to the ECM signaling molecule alone, whereby the
relative levels provide a basis for identifying either a promoter
or an inhibitor of cell adhesion.
EXAMPLE 25
Chondrogenesis--ECM Signaling Molecules Promote Cell
Aggregation
[0231] Since aggregation is an essential step for chondrogenic
differentiation (Solursh, M., In The role of extracellular matrix
in development, pp. 277-303 (Trelstad, R., ed.) (Alan R. Liss, New
York 1984)), the ability of Cyr61 to
EXAMPLE 26
Chondrogenesis--ECM Signaling Molecules Promote Cell
Proliferation
[0232] Some ECM signaling molecules, such as Cyr61, affect
chondrogenesis, as revealed by effects on limb bud mesenchyme cells
in micromass culture, as described above. Ahrens et al., Dev. Biol.
60:69-82 (1977), has reported that these cells, in micromass
culture, undergo chondrogenesis in a manner similar to the in vivo
process. Mesenchyme cells were obtained from mouse embryonic limb
buds by trypsin digestion (1 mg/ml, 1:250 dilution of porcine
pancreatic trypsin, Sigma Chemical Co.). Cells were explanted in
plastic tissue culture wells and allowed to attach for 2 hours at
37.degree. C., 5% CO.sub.2. Cells were then incubated for 24 hours
at 37.degree. C., 5% CO.sub.2 in MEM with 10% FBS, penicillin (50
U/ml), and streptomycin (50 .mu.g/ml). At this point, the
composition of the medium was changed by substituting 4% NuSerum
(Collaborative Biomedical Products, Inc.) for 10% FBS. Individual
cultures then received Cyr61, fibronectin, heparin (each at
approximately 1 .mu.g/ml) or buffer as a negative control. An
additional control was provided by adding a 1:100 dilution of
affinity-purified anti-Cyr61 antibody (approximately 13 .mu.g/ml
stock solution), elicited and purified by standard techniques.
Harlow et al.
[0233] Cell proliferation was assessed by the thymidine assay,
described above, and by microscopic cell counts. Chondrogenesis was
assessed by quantifying the incorporation of [.sup.35S]-sulfate
(ICN Biomedicals, Inc.) into sulfated glycosaminoglycans, and by
qualitatively determnining the extent of chondrogenesis by cell
staining with Alcian Blue. Cultures, described above, were labeled
with 2.5 .mu.Ci/ml [.sup.35S]-sulfate for 18 hours, washed twice in
PBS, fixed with Kahle's fixative (Pepper et al., J. Cell Sci.
109:73-83 [1995]) and stained for 18 hours in 0.5% Alcian Blue, pH
1.0. The extent of chondrogenesis is correlated with the intensity
of Alcian Blue staining. San Antonio et at., Dev. Biol. 115:313-324
(1986). The results show that Cyr61 specifically increased limb bud
mesenchyme cell proliferation and aggregation, leading to enhanced
chondrogenesis.
[0234] In addition to demonstrating that purified Cyr61 enhanced
growth factor-induced DNA synthesis in fibroblasts and endothelial
cells, the effects of Cyr61 on cell proliferation were directly
examined. Cell proliferation during the 4 day culture period was
determined by counting cell number and by incorporation of
[.sup.3H]-thymidine. To determine cell number, cells were harvested
by trypsin/EDTA (Sigma) and counted with a Coulter counter. In
parallel cultures, [.sup.3H]-thymidine (1 .mu.Ci/ml; ICN) was added
to the media for 18 hours and incorporation in the TCA-insoluble
layer was determined by liquid scintillation counting. Purified
Cyr61 protein added to limb mesenchymal cells both increased cell
number and enhanced DNA synthesis after 2 and 3 days in culture,
although the total cell number in Cyr61-treated and Cyr61-untreated
cultures leveled off at the same level after 4 days.
[0235] The role of Cyr61 in chondrogenesis may also improve the
integration of prosthetic devices. For example, skeletal injuries
and conditions frequently are treated by the introduction of a
prosthesis e.g., hip prosthesis, knee prosthesis. Beyond questions
of histocompatibility, the successful implantation of a prosthetic
device requires that the foreign element become integrated into the
organism's skeletal structure. The capacity of Cyr61 polypeptides
to affect cell adhesion, migration, and proliferation, and the
ability of Cyr61 polypeptides to induce the differentiation of
mesenchyme cells into chondrocytes, should prove valuable in the
treatment of skeletal disorders by prosthesis implantation. For
example, integration of a prosthetic device by chondrocyte
colonization would be promoted by therapeutic treatments involving
the administration of Cyr61 in a pharmaceutically acceptable
adjuvant, carrier or diluent, using any of the administration
routes known in the art or by coating the prosthesis device with
Cyr61 polypeptides in a suitable carrier. The carrier may also be a
slow-release type vehicle to allow sustained release of the
polypeptides.
[0236] As noted in previously, the methods of the invention include
a method of screening for modulators of cell proliferation,
including chondrocytes. A comparison of the relative rates of cell
proliferation in the presence of a control comprising an ECM
signaling molecule alone (e.g. Cyr61) and in the presence of a
combination of an ECM signaling molecule and a suspected modulator
of cell proliferation provides a basis for identifying a suspected
modulator as a promoter, or inhibitor, of chondrocyte
proliferation.
EXAMPLE 27
Chondrogenesis--ECM Signaling Molecules Promote Chondrogenesis
[0237] Chondrogenic differentiation was quantitated by
incorporation of [.sup.3S]-sulfate (ICN) into sulfated
glycosaminoglycans and assessed qualitatively by Alcian Blue
staining. Cultures were radiolabeled with 2.5 .mu.Ci/ml
[.sup.35S]-sulfate for 18 hr, fixed with Kahle's fixative and
stained with 0.5% Alcian Blue, pH 1.0 (Lev et al., 1964). The
extent of chondrogenesis is correlated with the intensity of Alcian
Blue staining (San Antonio et al., 1986). [.sup.35S]-Sulfate
incorporation in the fixed cell layer was quanititated by liquid
scintillation counting.
[0238] Exogenous purified Cyr61 protein promoted limb mesenchymal
cell aggregation and resulted in greater Alcian blue-staining
cartilaginous regions in micromass cultures, suggestive of a
chondrogenesis-promoting effect. This effect was quantified by the
incorporation of [.sup.35S]-sulfate into sulfated
glycosaminoglycans (San Antonio et al., 1986) in Cyr61-treated
micromass cultures. Exogenous Cyr61 enhanced [.sup.35S]-sulfate
incorporation in a dose-dependent manner, resulting in a 1.5-fold
and 3.5-fold increase with 0.3 and 5 .mu.g/ml Cyr61, respectively,
and was correlated qualitatively by increased Alcian Blue staining.
The increase observed at the 5 .mu.g/ml Cyr61 dose (120 nM) is an
under-estimation of the actual extent of chondrogenesis, since some
of the large cartilage nodules which were formed at this dose
detached from the dish. Cultures treated with 10 .mu.g/ml Cyr61
formed a more massive mound of cartilage.
[0239] A review of the literature indicated that chondrogenesis in
limb mesenchymal cell micromass cultures was increased 2-fold with
the addition of 10 .mu.g/ml heparin (San Antonio et al., [1987];
Resh et al., [1985]) and 3-fold with 50 .mu.g/ml tenascin (200 nM)
(Mackie et al., [1987]). The results demonstrated Cyr61-treated
cultures still showed an approximately 2-fold increase in
normalized sulfate incorporation over control, indicating that
Cyr61 promotes a net increase in chondrogenesis. On culture day 2,
the sulfate/cell number ratio was lower in Cyr61-treated cultures
compared to controls and is reflective of a low level of
[.sup.35S]-sulfate incorporation relative to cell number, since
mesenchymal cells are mostly proliferating rather than
differentiating in these early stage cultures (Ede, 1983).
[0240] The presence of endogenous Cyr61 in these cells, both in
vivo and in vitro, indicates that Cyr61 may indeed function
biologically to regulate chondrogenic differentiation. The ability
of exogenously added purified Cyr61 to promote intercellular
aggregation and to increase [.sup.35S]-sulfate incorporation and
Alcian-blue staining in limb mesenchymal cells demonstrates that
Cyr61 can act as a chondrogenesis enhancing factor. As shown above
in Example 11, anti-Cyr61 antibodies can neutlralize both the cell
adhesion and DNA-synthesis enhancement activities of Cyr61.
Anti-Cyr61 antibodies were added to the mesenchymal cell culture
media or mixed the cell suspension prior to plating. Chondrogenesis
was inhibited in the cultures treated with anti-Cyr61 antibodies.
as demonstrated by decreases of [.sup.35S]-sulfate incorporation to
50% and 30% of controls, when antibodies were added to the media,
and mixed with the cells, respectively. These observations were
correlated with decreased Alcian Blue staining. However, mixing of
the anti-Cyr61 antibodies with mesenchymal cells prior to plating
resulted in complete detachment in some of the treated cultures
within 24 hours.
[0241] To eliminate the possibility of an unidentified component in
the antibody preparation as a cause of cell detachment, anti-Cyr61
antibody was preincubated with 1 .mu.g/ml purified Cyr61 protein
prior to mixing with cells. The inhibition of chondrogenesis in
mesenchymal cells mixed with neutralized anti-Cyr61 antibodies was
abolished.
[0242] Generally, the invention contemplates a method of screening
for modulators of chondrogenesis. A comparative assay involves the
exposure of in such a way that the ECM signaling molecule's
activities are modulated or abolished.
[0243] Furthermore, because of the role played by ECM signaling
molecules such as Cyr61 in regulating chondrogenesis (i.e.,
skeletal development), genetic manipulations that alter the
expression of human Cyr61 may prove medically important for
prenatal screening methods and gene therapy treatments related to
skeletal conditions, in addition to angiogenic conditions. For
example, the cyr61 gene is expressed when mesenchymal cells of both
ectodermal and mesodermal origins differentiate to form
chondrocytes. Thus, one of the roles that Cyr61 might play is to
regulate the commitment of mesenchyme cells to chondrocyte cell
lineages involved in skeletal development. Consistent with this
view, transgenic mice overexpressing cyr61 ectopically are born
with skeletal abnormalities. In all cases examined, the presence of
the skeletal deformities correlates with expression of the
transgene. These results suggest that the human form of Cyr61 may
also regulate chondrogenesis and skeletal development. It is also
possible that the human cyr61 gene may correspond to a genetic
locus already known to affect skeletal development or birth defects
relating to bone morphogenesis. Knowledge of the human Cyr61
protein sequence, presented in SEQ ID NO:4 herein, and the coding
sequence of the cDNA, presented in SEQ ID NO:3 herein, provide the
basis for the design of a variety of gene therapy approaches.
[0244] This information also provides a basis for the design of
probes useful in genotypic analyses, e.g., Restriction Fragment
Length Polymorphism analyses. Such analyses are useful in the
fields of genetic counseling, e.g., in diagnosing diseases and
conditions and the likelihood of their occurrence, as well as in
forensic analyses.
[0245] By way of example, the materials of the present invention
are useful in the prenatal screening for a variety of conditions or
disorders, including blood disorders, skeletal abnormalities, and
cancerous conditions. Well known techniques for obtaining fetal
cells, e.g., amniocentesis, provide the materials
.alpha..sub.6.beta..sub.1 for both Cyr61 and CTGF. In addition to
its involvement in fibroblast adhesion, Cyr61 induces angiogenic
factors such as vascular endothelial growth factor (i.e., VEGF) in
these cells. It is expected that CTGF will also induce VEGF
expression.
[0246] Both Cyr61 and CTGF serve as bona fide signaling molecules
acting through adhesion receptors. Fibroblast adhesion to Cyr61 and
CTGF results in focal adhesion plaques, which can be visualized by
staining with either anti-.beta..sub.1 antibodies, or anti-focal
adhesion kinase (FAK), anti-paxillin, or anti-vinculin antibodies.
Morphologically, fibroblasts adhered to Cyr61 form filipodia,
consistent with a migratory response. Further, adhesion results in
the rapid tyrosine phosphorylation of FAK and paxillin, as well as
activation of MAP kinase and JNK kinase through phosphorylation.
Adhesion to Cyr61 results in altered gene expression in
fibroblasts, such as induction of MMP1 (collagenase, matrix
metalloproteinase 1).
[0247] The .alpha..sub.6.beta..sub.1 integrin is the adhesion
receptor for Cyr61 and CTGF in fibroblasts. Moreover, Cyr61
mediated adhesion through .alpha..sub.6.beta..sub.1 involves
concurrent binding to heparan sulfate proteoglycan. By contrast,
Cyr61 adhesion through .alpha..sub.V.beta..sub- .3 in endothelial
cells does not require binding to proteoglycans. Thus, the adhesion
of endothelial cells consists of two components: one mediated
through integrin .alpha..sub.V.beta..sub.3 and the other mediated
through .alpha..sub.6.beta..sub.1. A small amount of Cyr61-mediated
adhesion in endothelial cells that could not be blocked by LM609
has been observed. This residual adhesion was completely blocked by
anti-.alpha..sub.6.beta..sub.1 antibodies. Thus
.alpha..sub.6.beta..sub.1 is the primary receptor for Cyr61 in
fibroblasts, and the secondary receptor in endothelial cells.
[0248] The functional-blocking monoclonal antibodies against
integrins were purchased from Chemicon Inc: JBIA
(anti-.beta..sub.1); FB12 (anti-.alpha..sub.1); PIE6
(anti-.alpha..sub.2): PIB5 (anti-.alpha..sub.3); PIH4
(anti-.alpha..sub.4); PID6 (anti-.alpha..sub.5); NKI-GoH3
(anti-.alpha..sub.6); P3G8 (anti-.alpha..sub.V); LM609
(anti-.alpha..sub.V.beta..sub.3). Polyclonal anti-Cyr61 antibody
was raised in rabbits and affinity purified as described (Kireeva
et al., [1997]). Synthetic peptides GRGDSP (SEQ ID NO:31) and
GRGESP (SEQ ID NO:32) were purchased from Gibco-BRL. Heparin,
Chondroitin sulfate A, Chondroitin sulfate C, and Decorin were from
Sigma. Chondroitin sulfate B (Dermatan sulfate) and low molecular
weight (3K) heparin were from Fluka.
[0249] To further characterize Cyr61-mediated fibroblast adhesion,
Cyr61 variants or mutants were constructed that harbored alanine
substitutions within the putative heparin-binding sites between,
approximately, amino acids 280-290 and amino acids 306-312.
Constructions involved site-directed mutagenesis using a two-step
polymerase chain reaction (PCR) procedure. Briefly, two overlapping
internal oligonucleotide primers containing the altered sequences
in opposite orientation along with outside primers were used in two
separate PCR reactions. Mouse cyr61 cDNA was used as a template in
the first PCR reaction. Resulting products were gel purified,
combined, and used as a template for the second PCR reaction. The
final mutant PCR product was digested with BsrGI, which cuts at
sites flanking the mutated sequences. The BsrGI fragment containing
the wild-type cyr61 cDNA in the pSG5 vector was substituted with
the mutated PCR product. The orientation and mutations were
confirmed by DNA sequencing. Finally, the mutant cyr61 cDNA was
released from pSG5 by digestion with EcoRI from pSG5 and cloned
into the Baculovirus expression vector pBlueBac 4.5
(Invitrogen).
[0250] For the H1 mutant, the internal primers were
5'-GCGGCATGCAGCGCGACCGCGAAATCCCCAGAACCAGTC-3' (primer fH1; SEQ ID
NO:18) and 5'-TCGCGCTGCATGCCGCGCCCGCTTTTAGGCTGCTGTACACTG-3' (primer
rH1; SEQ ID NO:19). For the H2 mutant, the internal primers were
5'-GTCGCGGCATACGCGCCCAAATACTGCGGCTC-3' (primer fH2; SEQ ID NO:20)
and 5'-GCGCGTATGCCGCGACACTGGAGCATCCTGC-3' (primer rH2; SEQ ID
NO:21). The outside primers used in the second PCR reaction for
each mutant were 5'-CAGACCACGTCTTGGTCC-3' (upstream PCR primer; SEQ
ID NO:22) and 5'-GAATAGGCTGTACACTCGG-3' (downstream PCR primer; SEQ
ID NO:23). To construct a double mutant (dmcyr61), the H2 mutant
cyr61-containing pretreating cells with heparinase I (2 U/ml,
Sigma) or chondroitinase ABC (2 U/ml, Sigma) at 37.degree. C. for
30 minutes.
[0251] The ability of Cyr61 to mediate cell adhesion in normal
fibroblasts was investigated. Microtiter wells were coated with
purified recombinant Cyr61 protein, and 1064SK primary human
foreskin fibroblasts were allowed to adhere under serum-free
conditions. In particular, washed 1064SK fibroblasts were detached
with 2.5 mM EDTA and resuspended in serum-free DMEM medium at
2.5.times.10.sup.5 cells/ml. 50 .mu.l cell suspensions were plated
on microtiter wells coated with varying concentrations (0.5-5.0
.mu.g/ml) of Cyr61 protein. After incubation at 37.degree. C. for
30 minutes, adherent cells were fixed and stained with methylene
blue. Extracted dye was quantified by absorbance at 620 nm and
means from three trials showed an absorbance of about 0.3 A.sub.620
(0.5 .mu.g/ml Cyr61), with the absorbance ranging from 0.45-0.55
A.sub.620 for Cyr61 solutions of 1-5 .mu.g/ml, respectively.
Adhesion of 1064SK cells to Cyr61 was dose-dependent and
saturable.
[0252] In another experiment, microtiter wells were coated with
either BSA, Cyr61 (2 .mu.g/ml), or vitronectin (VN; 0.5 .mu.g/ml)
and blocked with affinity-purified anti-Cyr61 antibodies for one
hour at 37.degree. C. before 1064SK cells were plated. The
A.sub.620 for BSA-coated wells was about 0.05 with or without
anti-Cyr61 blocking antibody. With Cyr61-coated wells, the
A.sub.620 was 0.45 (without blocking antibody) or 0.15 (with
blocking antibody). With VN-coated wells, the A.sub.620 was about
0.55, with or without blocking antibody. These data are means of
triplicate determinations. The results showed that
affinity-purified anti-Cyr61 antibodies inhibited 1064SK cell
adhesion to Cyr61 but not to vitronectin, indicating that the
ability to mediate fibroblast adhesion was an intrinsic property of
the Cyr61 protein.
[0253] The effects of divalent cations in cell adhesion to Cyr61
was also investigated. Cells were added to microtiter wells coated
with Cyr61 (2 .mu.g/ml), Type I collagen (Col. 1, 2 .mu.g/ml),
Vitronectin (VN, 0.5 .mu.g/ml) or BSA (control); EDTA (2.5 m) or
Mg.sup.2+ (5.0 mM) was added to some cells. Cells were plated on
microtiter wells coated with Cyr61 (2 .mu.g/ml), and one of the
following components was added: Nothing, Ca.sup.2+, Mg.sup.2+,
Ca.sup.2+/Mg.sup.2+, or Ca.sup.2+/Mn.sup.2+(5.0 mM each); the
A.sub.620 values were 0.07, 0.46, 0.07, 0.46, 0.50, 0.08, and 0.48,
respectively. Data are means from triplicate determinations.
Fibroblast adhesion to Cyr61 was completely blocked by 2.5 mM EDTA
(about 0.12 A.sub.620), and was restored by the addition of 5.0 mM
Mg.sup.2+(0.50 A.sub.620). As expected, similar effects were
observed for fibroblasts plated on collagen (0.10 A.sub.620 with
EDTA, 0.58 A.sub.620 with Mg.sup.2+) or vitronectin (0.05 A.sub.620
with EDTA, 0.55 A.sub.620 with Mg.sup.2+). The presence of
Ca.sup.2+ abolished cell adhesion to Cyr61 competely, whereas the
addition of Mg.sup.2+ or Mn.sup.2+ had no effect. Inhibition by
Ca.sup.2+ is characteristic of adhesion through some members of the
.beta..sub.1 family of integrins, including receptors that bind
type I collagen, laminin, and vitronectin (integrins
.alpha..sub.2.beta..sub.1, .alpha..sub.6.beta..sub.1, and
.alpha..sub.V.beta..sub.1) in fibroblasts, as well as the
lymphocyte-specific integrin .alpha..sub.L.beta..sub.2. This
observation also helped to exclude some integrins whose adhesive
properties are supported by Ca.sup.2+. The presence of Mn.sup.2+,
but not Mg.sup.2+, was able to overcome the inhibitory effect of
Ca.sup.2+ on cell adhesion to Cyr61, suggesting that Mn.sup.2+ can
bind the Cyr61 adhesion receptor with higher affinity than
Ca.sup.2+.
[0254] A number of integrins expressed in fibroblasts, notably the
.alpha..sub.V integrins (.alpha..sub.V.beta..sub.1,
.alpha..sub.V.beta..sub.3 and .alpha..sub.V.beta..sub.3 vitronectin
receptors) and integrin .alpha..sub.5.beta..sub.1 (fibronectin
receptor), are sensitive to inhibition by RGD-containing peptides.
The effects of RGD peptides on Cyr61-mediated fibroblast binding
was tested by plating cells in wells coated with Cyr61 (2
.mu.g/ml). Type I collagen (2 .mu.g/ml) or vitronectin (0.5
.mu.g/ml), 2 mM GRGDSP or GRGESP peptide was then added. For
Cyr61-coated wells, no addition, GRGDSP, or GRGESP gave A.sub.620
values of about 0.50, 0.48, and 0.46, respectively. For Type I
collagen, the A.sub.620 values were 0.50, 0.47 and 0.49,
respectively, and for VN, the values were 0.45, 0.05, and 0.41,
repectively.
[0255] Cells were also pre-incubated with 40 .mu.g/ml monoclonal
antibodies against the integrin .alpha..sub.5 or the integrin
.alpha..sub.V subunits at room temperature for 30 minutes, then
plated on wells coated with Cyr61 (2 .mu.g/ml), vitronectin (0.5
.mu.g/ml) or fibronectin (FN, 1 .mu.g/ml). For Cyr61-coated wells,
the A.sub.620 values were 0.75 (no addition), 0.73
(anti-.alpha..sub.V), and 0.77 (anti-.alpha..sub.5); the
corresponding values for VN were 0.78, 0.32, and 0.72, for
fibronectin, the corresponding values were 0.72, 0.65, and 0.36.
The data are means, representative of three experiments. The
peptide RGDSP, but not the control peptide RGESP, completely
abolished 1064SK cell adhesion to vitronectin. By contrast, RGDSP
had no effect on fibroblast adhesion to Cyr61 or type I collagen.
This result indicated that fibroblast adhesion to Cyr61 is not
mediated through either the .alpha..sub.V integrins
(.alpha..sub.V.beta..sub.1 .alpha..sub.V.beta..sub.3, and
.alpha..sub.V.beta..sub.5) or .alpha..sub.5.beta..sub.1.
[0256] 1064SK cells were also challenged by pre-incubation with
monoclonal antibodies specifically recognizing the .alpha..sub.V
and .alpha..sub.5 integrin subunits. Whereas 1064SK adhesion to
vitronectin and fibronectin was blocked by monoclonal antibodies
against .alpha..sub.V and .alpha..sub.5, respectively, these
antibodies had no effect on adhesion to Cyr61. Thus, 1064SK
fibroblast adhesion to Cyr61 is mediated through one of the subset
of .beta..sub.1 integrins (e.g., .alpha..sub.2.beta..sub.1,
.alpha..sub.3.beta..sub.1, or .alpha..sub.6.beta..sub.1) known to
be inhibited by Ca.sup.2+ and insensitive to inhibition by
RGD-containing peptides.
[0257] The 1064 SK cells were also analyzed using the monoclonal
antibody JBIA, which binds the .beta..sub.1 integrin subunit. Cells
were pre-incubated with the antibody (50 .mu.g/ml) before plating
on microtiter wells coated with Cyr61 (2 .mu.g/ml), Type I collagen
(2 .mu.g/ml), or vitronectin (0.5 .mu.g/ml). Anti-.beta..sub.1
antibody inhibited cell adhesion to Cyr61 (A.sub.620 of 0.53
without antibody and 0.14 with antibody) by 75%, confirming that
1064SK fibroblast adhesion to Cyr61 requires the involvement of a
.beta..sub.1 integrin. As expected, adhesion to type I collagen was
inhibited by about 62% (A.sub.620 of 0.56 without and 0.21 with
antibody) by the anti-.beta..sub.1 antibody, whereas adhesion to
vitronectin was unaffected (A.sub.620 of 0.48 without, and 0.44
with, antibody). Data are means, representative of three
experiments.
[0258] To identify the specific .beta..sub.1 integrin that mediates
fibroblast adhesion to Cyr61, the inhibitory effects of
function-blocking monoclonal antibodies were tested against various
integrin .alpha. subunits. Cells were pre-incubated with monoclonal
antibodies against the integrin .beta.1 subunit (50 .mu.g/ml, see
results described above) or the integrin .alpha..sub.6 subunit (20
.mu.g/ml) at room temperature for 30 minutes, then plated on wells
coated with Cyr61 (2 .mu.g/ml), laminin (5 .mu.g/ml), or
fibronectin (1 .mu.g/ml). The data are means, representative of at
least three experiments. Monoclonal anti-.alpha..sub.6 antibody
blocked 1064SK fibroblast adhesion to Cyr61 (A.sub.620 of 0.53
without, and 0.08 with, antibody) by more than 80%, while having no
effect on adhesion to fibronectin. Adhesion to laminin, a ligand
for integrin .alpha..sub.6.beta..sub.1, was only partially blocked
(A.sub.620 of 0.62 without, and 0.48 with, antibody, or a block of
about 22%). Cells were pre-incubated with 40 .mu.g/ml monoclonal
antibodies against integrin .alpha.1, .alpha.2, .alpha.3 or
.alpha.4, or treated with a cocktail of .alpha.1, .alpha.2 and
.alpha.3 antibodies (40 .mu.g/ml each) at room temperature for 30
minutes, then plated on wells coated with Cyr61 (2 .mu.g/ml),
vitronectin (0.5 .mu.g/ml), or Type I collagen (2 .mu.g/ml). Data
are means, representative of three experiments, and are presented
in Table II.
2TABLE II Antibody Cyr61 (A.sub.620) VN (A.sub.620) Coll. I
(A.sub.620) None (control) 0.58 0.59 0.74 anti-.alpha..sub.1 0.54
0.57 0.62 anti-.alpha..sub.2 0.60 0.58 0.31 anti-.alpha..sub.3 0.55
0.54 0.63 anti-.alpha..sub.4 0.56 0.55 0.72 anti-.alpha..sub.1 +
anti-.alpha..sub.2 + anti-.alpha..sub.3 0.56 0.56 0.10
[0259] Function-blocking monoclonal antibodies against integrin
.alpha..sub.1, .alpha..sub.2, .alpha..sub.3 or .alpha..sub.5
subunits, or a combination of antibodies against .alpha..sub.1,
.alpha..sub.2 and .alpha..sub.3 had little effect on Cyr61-mediated
cell adhesion (Table II). In contrast, a mixture of
anti-.alpha..sub.1, anti-.alpha..sub.2, and anti-.alpha..sub.3
antibodies almost completely inhibited fibroblast adhesion to
collagen. Thus, 1064SK fibroblast adhesion to Cyr61 is mediated
through integrin .alpha..sub.6.beta..sub.1.
[0260] The role of heparin in the binding of fibroblasts to Cyr61
was also examined. First, various amounts of soluble heparin were
added to suspensions of 1064SK fibroblasts prior to plating on
either Cyr61- or fibronectin-coated wells. In particular, cells
were plated on wells coated with Cyr61 (2 .mu.g/ml) or fibronectin
(1 .mu.g/ml). Different amounts of heparin (0.001-1000 .mu.g/ml)
were included in the cell suspension before plating. Cells were
plated on wells coated with Cyr61 (2 .mu.g/ml) or vitronectin (0.5
.mu.g/ml). Data in trms of means, representative of at least three
experiments, showed that heparin levels as low as 1 ng/ml
detectably inhibited binding, with 0.1 .mu.g/ml or more completely
inhibiting cell adhesion to Cyr61. However, heparin levels up to
1000 .mu.g/ml had no effect on cell adhesion to fibronection.
[0261] The influence of chondroitin sulfates on cell adhesion to
Cyr61 was additionally examined. Cells were plated on wells coated
with Cyr61 (2 .mu.g/ml) or vitronectin (0.5 .mu.g/ml). Chondroitin
sulfate A (1 mg/ml), chondroitin sulfate B (100 .mu.g/ml),
chondroitin sulfate C (10 mg/ml), or decorin (100 .mu.g/ml) was
included in the cell suspension before plating. The data (three
trials) showed that 1 mg/ml chondroitin A or 10 .mu.g/ml of either
chondroitin B or decorin inhibited cell adheshion to Cyr61,
chondroitin C failed to inhibit adhesion to Cyr61 at all
concentrations tested (0.01-1000 .mu.g/ml). However, the
concentrations of chondroitin sulfates A, B, or decorin needed for
this inhibition were orders of magnitude higher than the effective
inhibitory concentration of heparan sulfate (e.g., 0.1 .mu.g/ml
heparan sulfate versus 1 mg/ml chondroitin sulfate A).
[0262] The addition of sodium chlorate (an inhibitor of
proteoglycan sulfation) to cell suspensions in Cyr61-treated (2
.mu.g/ml) wells resulted in a dose-dependent response, with 90%
inhibition of adhesion at 40 mM sodium chlorate. In contrast, this
concentration of chlorate resulted in only a 10-20% inhibition of
cell adhesion to other substrates (fibronectin, type I collagen,
vitronectin, and laminin). Data are means, representative of three
experiments. The chlorate inhibition study was conducted by
culturing cells in media containing 0-50 mM sodium chlorate for 24
hours, washing, and harvesting as described above, then plating on
Cyr61 92 .mu.g/ml), fibronectin (1 .mu.g/ml), Type I collagen
(Coll. 1, 2 .mu.g/ml), vitronectin (VN, 0.5 .mu.g/ml), or laminin
(5 .mu.g/ml). Chlorate-mediated adhesion inhibition was resuced by
the addition of 10 mM MgSO.sub.4. Cells were cultured in media
containing 50 mM sodium chlorate, or 50 mM sodium chlorate plus 10
mM magnesium sulfate for 24 hours, washed and harvested, then
plated on wells coated with Cyr61 (2 .mu.g/ml), vitronectin (0.5
.mu.g/ml), or fibronectin (1 .mu.g/ml).
[0263] The 1064SK fibroblasts were also treated with heparatinase,
which rendered cells unable to adhere to Cyr61 (A.sub.620 of 0.13
with, and 0.59 without, treatment), but had no effect on cell
adhesion to vitronectin (A.sub.620 of 0.63 with, and 0.70 without,
treatment) or fibronectin (A.sub.620 of 0.66 with, and 0.74
without, treatment). In contrast, chondroitinase A, B, C had no
effect (A.sub.620 values of 0.57, 0.69, and 0.65, for Cyr61,
vitronectin and fibronectin, respectively) on cell adhesion,
indicating that chondroitin sulfates do not contribute
significantly to human foreskin fibroblast adhesion to Cyr61. Thus,
cell surface proteoglycans, such as heparan sulfate proteoglycans,
are involved in Cyr61-mediated fibroblast cell adhesion. The
adhesion of human fibroblasts to Cyr61 is mediated through integrin
.alpha..sub.6.beta..sub.1, and sulfated proteoglycans play a role
in that adhesion.
[0264] Mutant Cyr61 proteins deficient in heparin binding were
generated to examine the effect of such changes on fibroblast
adhesion. Conventional site-directed multagenesis techniques were
used to produce mutant Cyr61 polypeptides having altered
heparin-binding motifs. Two pulative heparin-binding motifs were
found within the carboxyl-terminal domain in Cyr61 that conform to
the consensus XBBXB sequence for heparin binding (where B demots
basic amino acid residues such as lysine or arginine).
Site-directed mutagenesis was used to replace the lysine and
arginine residues in the motifs with alanine, thus creating two
Cyr61 variants (H1 and H2) each having one of the two heparin
binding motifs mutated. In addition, both motifs were mutated in a
Cyr61 double mutant (DM) variant. A comparison of the mutated amino
acid sequence
H.sub.2NSLKAGAACSATAKSPEPVRFTYAGCSSVAAYAPKYCG--CO.sub.2H (SEQ ID
NO:30) with residues 278-314 of SEQ ID NO:2 (wild-type mouse
Cyr61), shows clusters of amino acid changes between residues
280-290 (H1, underscored above) and between residues 305-310 (H2,
underscored above); both sets of clustered changes are found in DM.
These mutations were created using the full-length cyr61: the
mutant constructs were expressed in, and purified from, recombinant
Baculovirus-transformed insect cells. Equal amounts of conditioned
media of insect SF9 cells infected with Baculovirus expressing
wild-type or mutant Cyr61 protein were loaded on CL-6B Heparin
Sepharose columns. After washing with 20 bed volumes of RIPA
buffer, bound protein was eluted with RIPA buffer containing
increasing concentrations of sodium chloride. Equal amounts of
eluate from each fraction were analyzed on SDS-PAGE gels followed
by Western blotting to visualize Cyr61 protein. Antibodies used
were rabbit polyclonal antibodies against bacterial GST-Cyr61. The
H1 mutant Cyr61 polypeptide eluted over the range of 04-0.8 M NaCl;
DM eluted during the washing and up to 0.25 M NaCl; and wild-type
Cyr61 eluted at 0.8-1.0 M NaCl. These elution profiles indicate
that H1 and H2 exhibited somewhat decreased heparin-binding
affinities, whereas DM was severely deficient in heparin
binding.
[0265] To examine the activities of these Cyr61 variants (i.e.,
mutant Cyr61 proteins), various concentrations of the variants were
separately coated onto microtiter wells and 1064SK fibroblasts were
added. Adhesion assays were performed by optionally pre-incubating
cells with 20 .mu.g/ml monoclonal anti-.alpha..sub.6 antibody at
room temperature for 30 minutes, then plating on wild-type Cyr61,
mutant Cyr61 H1, mutant Cyr61 H2, or vitronectin (0.5 .mu.g/ml).
The results (three trials) showed that both H1 (e.g., 2.5 .mu.g/ml)
and H2 (e.g., 2.5 .mu.g/ml) were able to support fibroblast
adhesion with adhesion isotherms that were comparable to that of
wild-type Cyr61 (e.g., 2 .mu.g/ml), although maximal adhesion was
reached at a lower concentration of wild-type protein (1 .mu.g/ml)
compared to the mutant proteins (2.5-5.0 .mu.g/ml). Moreover,
adhesion to either H1 or H2 was blocked by antibodies against the
integrin subunit .alpha..sub.6, indicating that cell adhesion to
the mutant Cyr61 proteins is also mediated through integrin
.alpha..sub.6.beta..sub.1. In particular, the antibody inhibited
Cyr61-mediated binding by 78%, H1-mediated binding by 69%, and
H2-mediated binding by 70%, fibroblast binding to vitronectin was
only inhibited by 9%. Thus, the integrin .alpha..sub.6.beta..sub.1
binding sites of Cyr61 are distinct from the heparin-binding sites
mutated in H1 and H2. Mutant Cyr61 proteins that preserved wither
heparin-binding site exhibited sufficient residual heparin-binding
activity to support fibroblast adhesion. In contrast, DM was unable
to support 1064SK fibroblast adhesion at any concentration tested,
indicating that the intrinsic heparin binding activity of Cyr61 is
essential for mediating fibroblast adhesion.
[0266] Experiments designed to examine the effect of deleting the
carboxy-terminal domain of Cyr61 on Cyr61-mediated adhesion of
1064SK fibroblasts yielded consistent results in establishing that
the carboxy-terminal domain, containing the heparin binding site,
were necessary for fibroblast adhesion to Cyr61. The experiments
followed the protocol described above, but the recombinant human
cyr61 construct encoded Cyr61 NT, a Cyr61 polypeptide containing
amino acids 1-128 of SEQ ID NO:4 (i.e., lacking the
carboxy-terminal containing acid residues 282-381 of SEQ ID NO:4).
Thus, mature Cyr61 NT contains domains I, II and III, corresponding
to the IGFBP homology domain, the von Willebrand factor type C
repeat domain, and the thrombospondin type I repeat domain,
respectively, while lacking the heparan binding domain IV. Results
of the experiments demonstrated that Cyr61 NT did not support
fibroblast adhesion, although this Cyr61 polypeptide fragment did
support fibroblast migration, as described above (see Example 14).
Further, immunological analyses showed that an antibody (i.e.,
GoH3) specifically recognizing the integrin .alpha..sub.6 blocked
human fibroblast adhesion to Cyr61 polypeptides.
[0267] The following experiment showed that the requirement for
Cyr61 heparin binding sites was distinct from Cyr61-mediated
adhesion through the .alpha..sub.V.beta..sub.1 integrin. Washed
HUVE cells were detached by 2.5 mM EDTA and resuspended in
serum-free F-12K medium at 5.times.10.sup.3 cells/ml. Cells were
pre-incubated with 2.5 mM EDTA, 1 mM RGD peptide, or 40 .mu.g/ml
anti-.alpha..sub.6.beta..sub.3 monoclonal antibody (LM609) at room
temperature for 30 minutes, then plated on wild-type Cyr61 (5
.mu.g/ml), double-mutant Cyr61 (DM Cyr61 10 .mu.g/ml), or
vitronectin (0.5 .mu.g/ml). Immobilized cells were stained with
methylene blue and absorbances (A.sub.620) were recorded. relative
binding capacities (binding of cells not exposed to a
pre-incubation compound defined as 100%) are presented in Table
III.
3 TABLE III Pre-incubation Cyr61 DM Cyr61 Vitronectin None 100 100
100 EDTA 22 23 11 RGD peptide 50 23 13
Anti-.alpha..sub.v.beta..sub.3 antibody 42 23 89
[0268] The data were based on three independent trials. Thus, DM
still mediated HUVEC binding, establishing that the failure of DM
to bind to fibroblasts was specific to that cell type.
[0269] Cell adhesion assays were also performed on smooth muscle
cells. Bovine aortic smooth muscle cells (BASM cells) were
subjected to the cell adhesion assay described above in the context
of assaying fibroblasts. Results showed that Cyr61 polypeptides
induced adhesion of BASM cells. Heparin, but not "RGD" peptides
(see, e.g., SEQ ID NO:31), inhibited Cyr61-induced adhesion of the
smooth muscle cells. To identify particular integrin, receptors
mediating the Cyr61 induction of BASM cell adhesion, antibody
studies were conducted using anti-integrin antibodies recognizing
specific integrins. Antibody GoH3, recognizing integrin
.alpha..sub.6, completely abolished BASM cell adhesion. Similarly,
antibody JBla, specifically recognizing integrin .beta..sub.1,
eliminated Cyr61-induced BASM cell adhesion. Thus, integrin
.alpha..sub.6.beta..sub.- 1 mediates Cyr61-induced adhesion of
smooth muscle cells. It is expected that Cyr61 polypeptides that
include the heparan binding domain IV will induce adhesion of any
mammalian smooth muscle cell.
[0270] Accordingly, another aspect of the invention is directed to
a method of screening for a modulator of cell adhesion comprising
the steps of: (a) contacting a first fibroblast cell with a
suspected modulator of cell adhesion and a biologically effective
amount of an ECM signaling molecule-related biomaterial selected
from the group consisting of a Cyr61, a Fisp12, a CTGF, a NOV, an
ELM-1 (WISP-1), a WISP-3, a COP-1 (WISP-2), and fragments, analogs,
and derivatives of any of the aforementioned members of the CCN
family of proteins; (b) separately contacting a second fibroblast
cell with a biologically effective amount of an ECM signaling
molecule-related biomaterial described above, thereby providing a
control; (c) measuring the level of cell adhesion resulting from
step (a) and from step (b); and (d) comparing the levels of cell
adhesion measured in step (c), whereby a modulator of cell adhesion
is identified by its ability to alter the level of cell adhesion
when compared to the control of step (b). Preferably, the
fibroblast cells present the .alpha..sub.6.beta..sub.1 integrin.
Also preferred are fibroblast cells that present a sulfated
proteoglycan, such as heparan sulfate proteoglycan. Any one of a
number of CCN polypeptides may be used in the methods of the
invention, such as Cyr61 (mouse-SEQ ID NO:2, human-SEQ ID NO:4,
rat-Genbank Acc. No. AB015877), Fisp12/CTGF (mouse-SEQ ID NO:6,
human-SEQ ID NO:8, N. viridescens-Genbank Acc. No. AJ271167, Sus
scrofa-Genbank Acc. No. U70060, X. laevis-Genbank Acc. No.
AF120275), NOV (hyman-Genbank Acc. No. NM.sub.--002514,
mouse-Genbank Acc. No. Y09257, and G. gallus-Genbank Acc. No.
X59284), ELM-1 (Wisp-1; human-Genbank Acc. No. NM.sub.--003882,
mouse-Genbank Acc. No. AB004873), COP-1 (Wisp-2; human-Genbank Acc.
No. NM.sub.--003881, mouse-Genbank Acc. No. AF100778), and Wisp-3
(human-Genbank Acc. No. NM.sub.--003880).
[0271] Further, the invention comprehends screens for modulators of
interactions between ECM signaling molecules, such as human Cyr61
polypeptides, and .alpha..sub.6.beta..sub.1, a specific integrin
receptor whose activities include, but are not limited to,
mediating the adhesion of fibroblasts, smooth muscle cells and
endothelial cells. The screening methods involve contacting a Cyr61
polypeptide with .alpha..sub.6.beta..sub.1, preferably found in a
composition including a mammalian cell membrane such as an
endothelial, fibroblast or smooth muscle cell membrane, in the
presence and absence of a potential or suspected medulator of the
Cyr61-integrin interaction. Detection of relative levels of
interaction, preferably in the form of detecting elative levels of
cell membrane (or whole cell) adhesion, leads to the identification
of modulators. The invention further extends to methods of treating
conditions or disorders, such as diseases, associated with
excessive or inadequate cell adhesion, such as various forms of
fibrosis, defective angiogenesis, tumor growth, tumor metastasis,
granulation tissue disorders, inflammatory responses, and certain
muscle disorders known in the art. Treatment involves delivery of a
therapeutically effective amount of a Cyr61 polypeptide or a
modulator of the Cyr61-.alpha..sub.6.beta..sub.1 integrin receptor
interaction to a mammal such as a human by any means known in the
art.
[0272] The invention also contemplates analogous methods of
screening for modulators of fibroblast cell migration or
proliferation. The method described below identifies modulators of
cell migration; the described method applies to methods of
screening for modulators of cell proliferation by substituting the
parenthetically noted terms. A method of screening for modulators
of fibroblast cell migration comprises the steps of: (a) contacting
a first fibroblast cell with a suspected modulator of cell
migration (proliferation) and a biologically effective amount of an
ECM signaling molecule-related biomaterial selected from the group
consisting of a Cyr61, a Fisp12, a CTGF, a NOV, an ELM-1 (WISP-1),
a WISP-3, a COP-1 (WISP-2), and fragments, analogs, and derivatives
of any of the aforementioned members of the CCN family of proteins;
(b) separately contacting a second fibroblast cell with a
biologically effective amount of an ECM signaling molecule-related
biomaterial described above, thereby providing a control; (c)
measuring the level of cell migration (proliferation) resulting
from step (a) and from step (b); and (d) comparing the levels of
cell migration (proliferation) measured in step (c), whereby a
modulator of cell migration (proliferation) is identified by its
ability to alter the level of cell migration (proliferation) when
compared to the control of step (b). Preferred embodiments of the
methods of screening for modulators of either cell migration or
cell proliferation involve the use of fibroblasts presenting an
.alpha..sub.6.beta..sub.1 integrin and/or a sulfated
proteoglycan.
EXAMPLE 30
Cyr61-Mediated Regulation of Gene Expression
[0273] Soluble Cyr61 protein added to primary human foreskin
fibroblasts in culture elicits significant changes in gene
expression within 24 hours. In contrast, immobilized Cyr61 is
significantly less efficient in inducing such expression changes.
Among the changes that occur is: (1) upregulation of matrix
degrading enzymes, including MMP1, MMP3, and uPA; and (2)
downregulation of matrix protein genes such as the type I collagen
chain gene. Cyr61 also induces expression of the
inflammation-related proteins Il-1 and IL-6. In addition, Cyr61
induces a substantial upregulation of the VEGF1 (vascular
endothelial growth factor 1 or VEGF-A), a potent angiogenic factor,
and VEGF3 (VEGF-C), an important angiogenic factor for the
lymphatic system. These gene expression alterations indicate that
Cyr61 is useful in screening assays designed to identify modulators
of angiogenesis through detection of an effect on Cyr61
activity.
[0274] Purified, soluble, recombinant Cyr61 protein was added to
cultures of primary human foreskin fibroblasts for 24 hours. From
these cells, mRNA was isolated for preparation of probes to
hybridize to a multi-gene blot (Clontech Atlas Human Array 1.2 cat
no. 7850-1) containing about 650 genes. The levels of expression of
these genes in Cyr61-treated cells were compared to that of control
cells. From this comparison, it was found that the expression of
several groups of genes was altered: upregulation of matrix
degrading enzymes including MMP1, MMP3, and uPA; downregulation of
matrix protein genes such as the type I collagen chain gene;
induction of the inflammation-related cytokines IL-1 and IL-6, and
induction of the angiogenic molecules VEGF1 and VEGF3. These
findings have been confirmed by Northern blot analysis showing
increases or decreases of the mRNAs in question in Cyr61-treated
cells. A time course of expression changes has been established. In
particular, by 6 hours after its addition, Cyr61 has induced
expression of VEGF-A mRNA and the induction is still evident at 12
and 24 hours post-addition. Also at 12 and 24 hours post-addition,
Cyr61 has induced expression of VEGF-A polypeptide. With respect to
VEGF-C, induction of mRNA is clearly evident 12 hours after
addition of Cyr61 and the induction persists at least through 24
hours post-addition. Cyr61 is expected to induce the expression of
VEGF-C polypeptide with similar kinetics.
[0275] Cyr61 appears to be the key mediator for the action of
TGF-beta, which induces Cyr61 strongly and is known to regulate
matrix protein synthesis. Using mouse embryo fibroblasts derived
from Cyr61 knockout mice (see Example 31), it was shown that Cyr61
mediated TGF-beta function. Whereas TGF-beta can induce collagen
expression in embryo fibroblasts derived from a cyr61.sup..+-.
mouse (littermate of a cyr61.sup..+-. mouse), it cannot do so in
cells that have an insertional inactivation of cyr61 i.e., cyr61
knock-out cells). Also, TGF-beta can induce BEFG expression in
cyr61.sup..+-. fibroblasts, but not in cyr61.sup..+-.
fibroblasts.
[0276] Stimulation of fibroblasts by serum is known to induce the
expression of many genes. Whereas cyr61.sup..+-. cells respond to
scrum stimulation with the induction of VEGF, cyr61.sup..+-. cells
do not exhibit serum induction of VEGF (although the background
expression level is the same). This finding indicates that Cyr61 is
the mediator of VEGF induction under stimulation by serum growth
factors, and confirms the ability of Cyr61 to regulate VEGF
expression.
[0277] To prove that Cyr61-mediated serum induction of VEGF occurs
at the transcriptional level, collagen I and collagen II promoters
linked to reporter genes were transfected into cyr61 knock-out
cells and control cells. Consistent with the aforementioned
results, transcription from the transfected gene constructs was
induced by TGF-beta in control cells but not in knock-out
cells.
[0278] Thus, when fibroblasts are stimulated, Cyr61 expression can
lead to gene expression changes that produce proteins for matrix
degradation and remodeling, cytokines that are chemotatic for
macrophages and lymphocytes, and growth factors for
angiogenesis.
[0279] As noted above, Cyr61 polypeptides interact with the
.alpha..sub.6.beta..sub.1 integrin receptor of fibroblasts.
Additional gene expression studies have shown that both Cyr61 NT
(lacking the heparan binding domain IV) and dmCyr61 (containing
substitutions in the two consensus XBBXB heparan binding motifs at
amino acids 280-290 (H1) and 305-310 (H2) of SEQ ID NO:4) do not
induce the expression of the above-referenced genes (e.g., VEGF,
MMP1, and MMP3), in contrast to the effects of wild-type Cyr61.
Based on these results, the heparan binding domain of Cyr61 appears
to be required for induction of gene expression in fibroblasts. It
is expected that Cyr61 peptides such as TSP1 will inhibit gene
expression resulting from Cyr61 induction mediated by the
.alpha..sub.6.beta..sub.1 integrin receptor. It is also expected
that Cyr61 will induce the expression of these genes, and related
genes, in other mammalian cell types, and that the heparan binding
domain will be required for such induction regardless of cell
type.
[0280] The identification of target genes regulated by Cyr61,
including genes involved in matrix remodeling (wound healing,
metastasis, etc), inflammation, and angiogenesis, privides
indications of suitable targets of therapy using Cyr61.
[0281] Thus, in accordance with these findings, another aspect of
the invention is a method of screening for a modulator of
angiogenesis comprising the steps of: (a) contacting a first
endothelial cell comprising a cyr61 allele with a suspected
modulator of angiogenesis; (b) measuring the Cyr61 activity of the
first endothelial cell; (c) measuring the Cyr61 activity of a
second endothelial cell comprising a cyr61 allele; and (d)
comparing the levels of Cyr61 activity measured in steps (b) and
(c), thereby identifying a modulator of angiogenesis.
[0282] A related aspect of the invention is drawn to a method of
screening for a modulator of angiogenesis comprising the steps of:
(a) contacting a first endothelial cell with a polypeptide selected
from the group consisting of a Cyr61, a Fisp12, a CTGF, a NOV, an
ELM-1 (WISP-1), a WISP-3, a COP-1 (WISP-2), and fragments, analogs,
and derivatives of any of the aforementioned members of the CCN
family of proteins; (b) further contacting the first endothelial
cell with a suspected modulator of angiogenesis; (c) contacting a
second endothelial cell with the polypeptide of step (a); (d)
measuring the angiogenesis of the first endothelial cell; (e)
measuring the angiogenesis of the second endothelial cell; and (f)
comparing the levels of angiogenesis measured in steps (d) and (c),
thereby identifying a modulator of angiogenesis.
[0283] Another aspect of the invention is drawn to methods of
treating conditions or disorders, such as diseases, associated with
gene under- or over-expression by delivering a biologically or
therapeutically effective amount of an ECM Signaling Molecule
(e.g., a Cyr61 polypeptide, Fisp12, CTGF), or modulator of a
Cyr61-integrin receptor interaction, using delivery means known in
the art. A therapeutically effective amount of an ECM Signaling
Molecule is that amount that results in mitigation of the gene
under- or over-expression. Genes whose expression can be affected
by an ECM Signaling Molecule include, but are not limited to, MMP1,
MMP3, uPA, the type I collagen chain gene, the inflammation-related
cytokines IL-1 and IL-6 and the genes encoding the angiogenic
molecules VEGF1 and VEGEF3. Exemplary conditions, disorders and
diseases include excessive or inadequate cell adhesion, such as
various forms of fibrosis, defective angiogenesis, tumor growth,
tumor metastasis, granulation tissue disorders, inflammatory
responses, and certain muscle disorders known in the art.
[0284] The methods of identifying modulators of angiogenesis take
advantage of the potential for modulators to influence angiogenesis
by affecting the activity levels of a CCN protein such as Cyr61 by
either influencing the level of expression of the protein or by
influencing the specific activity of the expressed protein.
EXAMPLE 31
Cyr61 Knock-out Mice
[0285] The mouse cyr61 gene was insertionally inactivated (i.e.,
knocked out) in vivo by targeted gene disruption and the phenotypes
of heterozygous and homozygous knock-out mice were examined.
Heterozygous mice (cyr61.sup..+-.) appeared to be normal, as these
mice did not exhibit any apparent phenotype. The cyr61.sup..+-.
homozygous mice, however, exhibited severe vascular defects and
apparent neuronal defects as well. Most of the cyr61.sup..+-. mice
died in utero, starting from E10.5 through parturition, with most
embryos dying around E13.5. There is a spectrum of developmental
defects and phenotypes at the time of embryonic death.
[0286] The initial step in preparing knock-out mice was to
construct a targeting vector that contained the mouse cyr61 gene
insertionally inactivated by introducing the bacterial lacZ gene
encoding .beta.-galactosidase, which facilitated screening for
knock-out mice. A commercially available 129 Sv1 mouse genomic DNA
library (Stratagene) was screened with a cyr61 probe and Clone 61-9
was identified. Clone 61-9 phage DNA was then prepared and digested
with Stul and BamHI using conventional techniques. The 6 kb
fragment containing the cyr61 promoter and coding region was
ligated to a blunt-ended Kpnl linker, thereby attaching the linker
to the Stul site. The fragment was then digested with BamHI and
Kpnl and inserted into BamHI, Kpnl digested pBluescript KS+. The
recombinant pBluescript KS+ was cut with Smol and then ligated to
an Xhol linker. After linker ligation, the recombinant plasmid was
cut with Xhol and the Xhol fragment bearing the lacZ coding region
from pSA.beta.gal (Friedrich et al., Genes Dev. 5:1513-1532 (1991))
was inserted. The PGK-TK-blue plasmid containing a thymidine kinase
gene driven ty the PGK promoter (Mansour et al., Nature 336:348-352
(1988)) was cut with EcoRI and the ends were blunted with Klenow.
The blunt-ended fragment was then ligated to Kpnl linkers. Finally,
the cyr61-.beta.gal-neo DNA and the modified PGK-TK DNA were each
cut with Kpnl and ligated to generate p61geo, the final targeting
construct. Thus, p61geo contained functional .beta. gal and neo
coding regions flanked on the 5' side by a 1.7 kb fragment
containing an intact cyr61 promoter and flanked on the 3' side by a
3.7 kb fragment containing the 3' end of the cyr61 coding region
(exons 2-5 and 3' flanking sequence). Homologous recombination of
this insert into the mouse chromosome would disrupt the cyr61
coding region and place the .beta.gal and neo coding regions into
the genome.
[0287] Cell culturing was performed according to Genome Systems
instructions for mouse embryonic fibroblasts (MEFs), or as
described by Li et al., Cell 69:915-926 (1992), with modifications,
for Jl ES cells. Briefly, MEFs were cultured in 7.5% CO.sub.2 in an
incubator at 37.degree. C. with DMEM (high glucose) medium
(Gibco/BRL#11965-084) and 10% heat-inactivated Fetal Calf Serum
(HyClone), 2 mM glutamine 0.1 mM non-essential amino acids, and
optionally with 100 U of Penicillin/Streptomycin. MEFs were
isolated from mouse embryos at E14.5 and supplied at passage 2.
[0288] For feeder cells, MEFs were mitotically inactivated by
exposure to 10 .mu.g/ml Mytomycin C(Sigma) in culture medium at
37.degree. C. (7.5% CO.sub.2) for 2-5 hours. Cells were then washed
3 times with PBS. Mitotically inactivated MEFs were harvested with
trypsin-EDTA(Gibco/BRL) and plated about 1.times.10.sup.3/cm.sup.2
with MEF medium.
[0289] Jl embryonic stem(ES) cells were cultured in DMEM (no
pyruvate, high glucose formulation; Gibco/BRL# 11965-084)
supplemented with 15% heat inactivated FCS (Hyclone), 2 mM
glutamine (Gibco/BRL), 0.1 mM non-essential amino acids(Gibco/BRL),
10 mM HEPES buffer (Gibco/BRL), 55 .mu.M .beta.-mercaptoethanol
(Gibco/BRL), and 1,000 U/ml ESGRO (leukemia inhibitory factor,
LIF)(Gibco/BRL). Jl cells were routinely cultured in ES medium on a
feeder layer of mitotically inactivated MEFs in a humidity
saturated incubator at 37.degree. C. in 7.5% CO.sub.3. Normally,
1.5.times.10.sup.6 Jl cells were seeded in a 25 cm.sup.2 tissue
culture flask and the medium was changed every day. Cell cultures
were divided 2 days after seeding, usually when the flask was about
80% confluent. To dissociate ES cells, cells were washed twice with
PBS (Ca- and Mg-free) and trypsinized with Trypsin/EDTA at
37.degree. C. for 4 minutes. Cells were than detached, mixed with
trypsin/EDTA thoroughly, and incubated for an additional 4 minutes.
The cell suspension was then pipetted several (20-30) times to
break up the cell clumps. A complete dissociation of cells was
checked microscopically. ES cells were frozen with ES medium having
10% FCS and 10% DMSO(Sigma) at about 4-5.times.10.sup.6 cells/ml,
with 0.5 ml/tube. Frozen cells were stored at -70.degree. C.
overnight and transferred into liquid nitrogen the next day. Frozen
cells were quickly thawed in a 37.degree. C. water bath, pelleted
in 5 ml ES medium to remove DMSO, and plated in 25 cm.sup.2 flasks
with fresh MEF feeder cells.
[0290] To transfect mouse cells with a transgene, the p61 geo
targeting construct was linearized by Not1 digestion, suspended in
PBS at 1 .mu.g/ml, and introduced into Jl ES cells by
electroporation. Rapidly growing (subconfluent, medium newly
refreshed) Jl ES cells were trypsinized, counted, washed and
resuspended in the electroporation buffer containing 20 mM HEPES,
pH 7.0, 137 mM NaCl, 5 mM KCl, 6 mM D-glucose, and 0.7 mM
Na.sub.2HPO.sub.1, at 1.times.10.sup.7 cells/ml. Linearized DNA was
added to the cell suspension at 45 .mu.g/ml, mixed, and incubated
at room temperature for 5 minutes. A 0.8 ml aliquot of cell-DNA mix
was then transferred to a cuvette and subjected to electroporation
with a BioRad Gene Pulser using a single pulse at 800 V, 3 .mu.F.
Cells were left in the buffer for 10 minutes at room temperature,
and then plated at 4.times.10.sup.6 cells/100 mm plate with
neomycin-resistant MEF feeder cells. Cells were then cultured under
standard conditions without drug selection. After 24 hours,
selection medium containing ES medium supplemented with 400
.mu.g/ml (total) G418 (Gibco/BRL) and 2 .mu.M Ganciclovir (Roche)
was substituted. Selection medium was refreshed daily. Individual
colonies were placed in microtiter wells and cells were dissociated
with 25 .mu.l 0.25% trypsin-EDTA/well on ice and subsequently
incubated in a humidified incubator at 37.degree. C. with 7.5
CO.sub.2, for 10 minutes. Cell suspensions were then mixed with 25
.mu.l ES medium and pipetted up and down 10 times to break up
clumps of cells. The entire contents of each well were then was
transferred to a well in a 96-well flat-bottom dish with 150 .mu.l
of ES medium in each well and grown using conventional culturing
techniques for 2 days.
[0291] Confluent ES cell clones were washed and treated with lysis
buffer (10 mM Tris (pH 7.7), 10 mM NaCl, 0.5% (w/v) sarcosyl, and 1
mg/ml proteinase K) in a humid atmosphere at 60.degree. C.
overnight. After lysis, a mixture of NaCl and ethanol (150 .mu.l of
5 M NaCl in 10 ml of cold absolute ethanol) was added (100
.mu.l/well) and genomic DNA was isolated. The genomic DNA of each
ES cell clone was digested with EcoRI (30 .mu.g/well) and subjected
to Southern blot assay.
[0292] Southern blotting was preformed as described in "Current
Protocols in Molecular Biology" (Ausubel et al., [1999]). Briefly,
EcoRI fragments of genomic DNA were fractionated by electrophoresis
through 0.8% agarose gels and blotted onto nylon membranes
(Bio-Rad) by downward capillary transfer with alkaline buffer (0.4
M NaOH). The probes, a BumHI-EcoRI fragment 3' to the long arm of
the targeting construct (p61geo) or the neo coding region
sequences, were prepared by random primer labeling (Prim-it II,
Stratagene) using [.alpha.-.sup.32P] dCTP (NEN). Membranes were
prehybridized in hybridization buffer (7% SDS, 0.5 M NaHPO.sub.4
(pH 7.0), and 1 mM EDTA) at 65.degree. C. for 15 minutes in a
rolling bottle. Fresh hybridization buffer was added with the probe
and membranes were hybridized for 18 hours. Hybridized membranes
were briefly rinsed in 5% SDS, 40 mM NaHPO.sub.4 (pH 7.0), 1 mM
EDTA and then washed for 45 minutes at 65.degree. C. with fresh
solution. This wash solution was replaced with 1% SDS, 40 mM
NaHPO.sub.4 (pH 7.0), 1 mM EDTA and washed twice for 45 minutes at
65.degree. C. with fresh solution. After washing, membranes were
exposed to a screen, which was then scanned using a Phosphorimager
(Molecular Dynamics). Blots were routinely stripped and re-probed
with the control neo probe to ensure that random integration had
not occurred, using conventional techniques.
[0293] Results of the Southern analysis showed that the genomic DNA
of 14 colonies (231 colonies examined) contained a mutant cyr61
allele in a location consistent with integration via homologous
recombination. The sizes of the detected fragments were 6.4 kb for
the wild-type cyr61 allele and 7.4 kb for the mutant allele with
the cyr61 probe, no brand for the wild-type cyr61 allele and a 7.4
kb band for the mutant allele with the neo probe.
[0294] Genotyping was also done by PCR using a RoboCycler
(Stratagene). Primers were designed to amplify a 2.1 kb DNA
fragment from mutant alleles. The PCR product covers the 5'-flank
of the short arm of the targeting construct through to the sequence
of lazZ (.beta.-gal) within the targeting construct. The upper PCR
primer acquence was 5'-CACAACAGAAGCCAGGAACC-3' (SEQ ID NO:24) and
the lower PCR primer sequence was 5'-GAGGGGACGACGACAGTATC-3' (SEQ
ID NO:25). PCR reaction conditions were 95.degree. C. for 40
seconds, 63.degree. C. for 40 seconds, and 68.degree. C. for one
minute, for 35 cycles.
[0295] For genotyping mouse tails or embryo tissues, two sets of
primers were included in the same PCR reaction to amplify both
wild-type and mutant alleles. A single upper PCR primer (b) was
used, which had the sequence 5'-CAACGGAGCCAGGGGAGGTG-3' (SEQ ID
NO:26). The lower PCR primer for amplifying the wild-type allele,
lower wt primer, had the sequence 5'-CGGCGACACAGAACCAACAA-3' (SEQ
ID NO:27) and would amplify a fragment of 388 bp. The lower PCR
primer for amplifying the mutant allele was the lower mutant primer
and had the sequence 5'-GAGGGGACGACGACAGTATC-3' (SEQ ID NO:28); a
600 bp fragment was amplified from mutant alleles. Reaction
conditions were 95.degree. C. for one minute, 63.degree. C. for one
minute, and 72.degree. C. for one minute, for 30 cycles.
[0296] PCR amplification of mutant alleles of cyr61 using the
mutant-specific primers produced a fragment of 2.1 kb and attempts
to amplify the wild-type allele with those primers failed to
produce a detectably amplified fragment, in agreement with
expectations. Southern analyses identified a 7.4 kb band (mutant
allele) and a 6.4 kb band (wild type) in heterozygous mutants; only
the 6.4 kb band was detected when probing wild-type DNAs. Both the
PCR data and the Southern data indicate that mutant cyr61 alleles
were introduced into the mouse genome in a manner consistent with
homologous recombination.
[0297] The selected ES cell clones were then expanded for
micro-injection into E3.5 blastocysts from C57BL/6J mice. Embryo
manipulations were carried out as described by Koblizek et al.,
Curr. Biol. 8:529-532 (1998) and Suri et al., Science 282;468-471
(1998), with modifications. Briefly, the Jl ES cell clones were
harvested and dissociated with trypsin-EDTA. The cells were
resuspended in CO.sub.2-independent medium (Gibco-BRL) with 10% FBS
and kept on ice. About 15-20 ES cells were injected into each
blastocyst from C57BL/6J (Jackson Labs), injected blastocysts were
cultured for 1-2 hours prior to transfer into the uterine horns of
pseudopregnant foster mothers (CD-1, Harlan). Chimeras were
identified by coat color. Male chimeras with a high percentage of
agouti coat color were caged with C57BL/6J females to test
germ-line transmission of the ES-cell genotype F, offspring
carrying the targeted (i.e., mutant) allele were then back-crossed
with C57BL/6J females for a few rounds to establish an inbred C57BL
genetic background. In addition, a mutant mouse line having the
inbred 129SvJ genetic background was obtained by mating germ-line
chimera males with 129SvJ females.
[0298] Five ES cell clones were injected and generated chimeric
offspring with ES cell contributions ranging from 30%-100%, as
judged by the proportion of agouti coat color. Four and two
chimeric males derived from ES cell clones 4B7 and 2A11,
respectively, efficiently transmit the targeted allele through the
germline. The cyr61 heterozygous mutant mice appeared healthy and
fertile. The 4B7 chimeric line was either bred to 129SvJ mice to
maintain the targeted allele in a SvJ129 genetic background, or
back-crossed with C57BL/61 mice to transfer the mutation into the
C57BL/61 background. The 2A11 targeted line was maintained in the
129SvJ genetic background. Similar phenotypes were exhibited by the
4B7.sub.129, 4B7.sub.CSTBL, and 2A11 mouse lines.
[0299] Among the offspring from intercrosses of cyr61.sup..+-. mice
that were examined, 141 were cyr61.sup..+-., 225 were
cyr61.sup..+-., and no homozygous cyr61.sup..+-. mice were observed
at this age, except that 10 cyr61.sup..+-. pups were born alive and
died within 24 hours of birth. Based on Mendelian ratios, the
majority (>90%) of the cyr61.sup..+-. animals should have died
before birth. Thus, staged prenatal fetuses were examined by PCR,
ad described above. Starting from E10.5, the numbers of homozygous
mutant embryos were found to be less than expected based on a
Mendelian ration, which might have been due to resorption of
homozygous mutant embryos. However, most (80%) of the E10.5
cyr61.sup..+-. embryos appeared normal compared to littermates. At
this stage (E10.5), the failure of chorioallantoic fusion was found
in some embryos and this phenotype resulted in early embryonic
lethality. The allantois of this type of embryo appeared
ball-shaped and often was filled with blood. While no other defects
were specifically identified, hemorrhage began to appear in a few
of the cyr61-null embryos.
[0300] At E11.5, about 50% of cyr61.sup..+-. embryos were
indistinguishable from wild-type or heterozygous mutant littermates
by appearance. By E11.5, embryos lacking a chorioallantoic fusion
were consistently deteriorated. Increasing numbers and severity of
hemorrhage were also observed in cyr61-null embryos. Hemorrhages
occurred in different areas, including the placenta, intra-uterus,
intra-amnion, embryo body trunks, body sides, and head. At this
stage, placental defects were also found in some null mutant
embryos. The placentae associated with these embryos showed a
sub-standard vasulature network. Unlike the early lethality
associated with the failure of chorioallantoic fusion, embryos with
placental defects typically lived and developed normally.
[0301] At E12.5, cyr61.sup..+-. embryos still presented three
phenotypes: 1) unaffected, 2) alive with hemorrhage and/or
placental defects, and 3) deteriorated, though with the proportion
of categories changed from earlier stages. About 30% of the
cyr61-null embryos remained unaffected at this stage. About 50% of
the null mutant embryos showed signs of hemorrhage and/or placental
defects and 20% of this type of embryo did not survive the vascular
or the placental defects. About 20% of cyr61.sup..+-. embryos did
not have a chorioallantoic fusion and died at much earlier stages,
as judged by the under-development of defective embryos.
[0302] By E13.5, none of the cyr61.sup..+-. embryos that had shown
hemorrhage, placental defects, or failure of chorioallantoic fusion
were alive, although about 30% of the total Cyr61-deficient embryos
showed no apparent phenotype. Embryos examined at later stages
(>E14.5) showed the same phenotypic pattern and the same
proportion for each type of defect, but with increasing
severity.
[0303] Additional investigation, at the cellular and sub-cellular
levels, was performed using the following techniques. MEF cells
were harvested as described by Hogan et. al., Manipulating the
Mouse Embryo. A Laboratory Manual (1994). Briefly, E11.5 embryos
from crosses of two heterozygous cyr61-targeted parents were
dissected in DMEM without serum. The limbs, internal organs, and
brain were removed. Embryo carcasses were then minced with a razor
blade and dissociated with trypsin/EDTA at 37.degree. C. with
rotation for 10 minutes. Half of the dissociation buffer was then
added to an equal volume of DMEM plus 10% FBS. Dissociation and
collection steps were repeated five times. Collected cells were
expanded and split at a 1:10 ratio to select the proliferating
fibroblast cells.
[0304] To prepare total cell lysates, a 100 mm plate of MEF cells
was cultured to near confluency. Cells were activated with fresh
medium containing 10% serum and incubated at 37.degree. C. for 1.5
hours before being harvested. Cells were then washed and
centrifuged using conventional procedures. The cell pellets were
resuspended in 100 .mu.l RIPA buffer (0.5% sodium deoxycholate,
0.1% SDS, 1% Nonidet P-40, 50 mM Tris-Cl, pH 8.0, 150 mM NaCl,
aprotinin 0.2 units/ml, and 1 mM PMSF) and put on ice for 10
minutes to lyse the cells. The cell suspension was centrifuged and
the supernatant (cell lysate) was stored at -70.degree. C. for
further analysis. One third of the supernatant was subjected to
Western blot analysis using a TrpE-mCyr61 polyclonal
anti-serum.
[0305] To confirm that homozygous cyr61.sup..+-. animals did not
express Cyr61, MEF cells were prepared from E11.5 embryos resulting
from intercrosses of two cyr61.sup..+-. parents. Cell lysates were
collected from serum-stimulated MEFs of different genotypes and
were subjected to Western blot analyses using anti-Cyr61 antiserum
(trpE-mCyr61). The Western blot demonstrated that the Cyr61 protein
level was not detectable in KO (knockout) MEF cells, while
heterozygous cyr61.sup..+-. cells expressed the Cyr61 protein at
high levels under the same culture conditions and serum
stimulation. The lack of expression of Cyr61 in cyr61.sup..+-.
animals was further confirmed by Northern blot analyses, in which
cyr61 mRNA was not detectable in serum-induced KO MEF cells. Thus,
the null mutation of cyr61.sup..+-. has been confirmed as
eliminating Cyr61 expression at both the mRNA and protein
levels.
[0306] Defects in placental development, a major cause of embryonic
death in cyr61.sup..+-. mice, were further analyzed. Histological
analyses of mouse placentac generally followed Suri et al., (1998).
Briefly, placentae from E12.5 embryos were dissected in cold PBS
and fixed with 4% paraformaldehyde in 0.1 M phosphate buffer (PB)
at 4.degree. C. for overnight. Fixed placentae were then dehydrated
through increasing concentrations of alcohol (50%, 75%, 90%, 95%,
and 100%) two times. Dehydrated tissue was then cleared with
Hemo-De (a xylene alternative), 1:1 ethanol/Hemo-De (Fisher), and
100% Hemo-De, and the clearing process was repeated. Cleared
tissues were then equilibrated in a 1:1 mixture of paraffin:Hemo-De
at 60.degree. C. for one hour in a vacuum oven and the process was
repeated. Tissues were embedded in paraffin with Histoembedder
(Leica). The paraffin-embedded placentae were cut into 10 .mu.m
slices with a nicrotome (Leica). Finally, tissue sections were
subjected to Harris' Hematoxylin and Eosin staining (Asahara et
al., Circ. Res. 83:233-240 [1998]).
[0307] Placentae for immunohistochemical staining were dissected in
cold PBS and fixed in 4% paraformaldehyde at 4.degree. C.
overnight. Fixed tissue was transferred to 30% sucrose in PBS at
4.degree. C. overnight. Placentae were then embedded in OC.T.
(polyvinyl alcohol, carbowax solution) on dry ice. Frozen blocks
were stored at -70.degree. C. or cut into 7 .mu.m sections with a
cryotome (Leica). Immunohistochemical staining was done as
recommended by the manufacturer (Zymed). Briefly, frozen sections
were post-fixed with 100% acetone at 4.degree. C. for 10 minutes.
Endogenous peroxidase was blocked with Peroxo-Block (Zymed).
Sections were incubated with a 1:250 dilution of biotinylated rat
anti-mouse PECAM-1 (i.e., platelet endothelial cell adhesion
molecule-1) monoclonal antibody MEC 13.3 (Pharmingen) at 4.degree.
C. overnight. A Histomouse-SP kit with Horse Radish Peroxidase
(Zymed) was used to detect PECAM-1 signals.
[0308] The results of histological and immunohistochemical analyses
showed that Cyr61-null placentae contained a limited number of
embryonic blood cells and were largely occupied by maternal blood
sinuses. Abnormally compact trophoblastic regions were also
observed. PECAM-1 staining demonstrated the highly-vascularized
labyrinthine zone in a heterozygous mutant placenta. Under higher
magnification, flows of fetal blood cells within the PECAM-1
stained vessels were identified. Consistent with the variation in
phenotypes among the Cyr61-deficient embryos, the staining of
placentae from numerous Cyr61.sup..+-. embryos also reflected
placental defects to various degrees. Nonethless, the placental
defects observed with PECAM-1 staining can be classified into two
groups, groups I and II. Group I of type-II (type I-embryos with
complete failure of chorioallantoic fusion not surviving E10.5,
type II-embryos with partially defective chorioallantoic fusion
surviving through about E13.5) exhibits a set of placental defects
that is characterized by the virtual absence of embryonic vessels,
the presence of condensed trophoblasts, and the presence of a
compressed labyrinthine zone. A higher magnification view confirms
that no vessels developed in the labyrinthine with placental
defects of this kind. Placentae with a group II defect showed fair
amounts of PECAM-1-positive staining and condensed capillary
structures. However, the PECAM-1-stained vessel-like structures
were degenerated and collapsed, with no fetal blood cells
inside.
[0309] Thus, the lack of Cyr61 causes two types of placental
defects. In type I, the failure of chorioallantoic fusion results
in the loss of physical connection between the embryo and the
placenta. In type II placental defects, the physical connection is
established by successful chorioallantoic fusion. However, the
embryonic vessels only reach to the surface of the placenta or,
with successful penetration through the chorionic plate, develop an
immature non-functional vascular structure in the labyrinthine
zone.
[0310] X-gal staining was also used to assess embryonic development
in various xyr61 backgrounds. (The targeting DNA, p61 geo, was
designed to knock out the Cyr61 gene and also to "knock in" in
.beta.-gal gene as a marker to reflect the expression of Cyr61).
X-gal (i.e., 5-Bromo-4-chloro-3-indolyl-.beta.-D-galactopyranoside)
staining for .beta.-galactosidase expression was performed on
heterozygous cyr61.sup..+-. embryos staged from E9.5 to E11.5. The
staining was done as described (Suri et al., [1998]). Staged
embryos were fixed in a 0.2% paraformaldehyde solution at 4.degree.
C. overnight. Fixed tissue was incubated in 30% sucrose in PBS plus
2 mM MgCl.sub.2 at 4.degree. C. overnight. Tissue was then embedded
in OCT on dry ice and cut with a cryotome into 7 .mu.m sections.
Frozen tissue sections were post-fixed in 0.2% paraformaldehyde and
stained with X-gal (1 mg/ml) at 37.degree. C. for 3 hours in the
dark. Slides were counter-stained with 1% Orange G. Stained slides
were then serially dehydrated through increasing concentrations of
methanol, cleared with Hemo-De, and slides were mounted.
[0311] X-gal staining of the E9.5 embryos, including the
extra-embryonic tissues, showed .beta.-galactosidase expression,
driven by the cyr61 promoter, at the tip of the allantois adjacent
to the chorion in the chorioallantoic placenta. The staining of
more advanced E10.5 embryos illustrated that large vessels
branching from the allantoic vessels were developed in the
chorionic plate and could easily be identified in the endothelial
lining using X-gal. Further developed E11.5 placenta showed the
same expression pattern as E10.5 embryos. While the staining was
highly associated with the endothelium of the umbilical and
chorionic vessels, no detectable staining in the labyrinthine zone,
where a microvasculature network was developing, was seen at E11.5.
The presence of Cyr61 in the allantois al, and proximal to, the
fusion surface with the chorion, and in the umbilical and chorionic
vessels, further supports the important role of Cyr61 in
angiogenesis. Cyr61 was involved in chorioallantoic fusion and was
critical for proper angiogenic development as placentation
progressed. Moreover, a staining of the E11.5 embryo confirmed that
Cyr61 was expressed in the paired dorsal aortae and the major
arteries branching from the heart, which is consistent with the
hemorrhaging seen in Cyr61-null mutants.
[0312] Apparent from the preceding description is another aspect of
the invention, which is directed to a method of screening for
modulators of angiogenesis comprising the steps of: (a)
constructing a non-human transgenic animal comprising a mutant
allele of a gene encoding a polypeptide selected from the group
consisting of a Cyr61, a Fisp12, a CTGF, a NOV, and ELM-1 (WISP-1),
a WISP-3, a COP-1 (WISP-2); (b) contacting the transgenic animal
with a suspected modulator of angiogenesis; (c) further contacting
a wild-type animal of the same species with the polypeptide,
thereby providing a control; (d) measuring the levels of
angiogenesis in the transgenic animal; (e) measuring the level of
agiogenesis of the wild-type animal; and (f) comparing the levels
of angiogenesis measured in steps (d) and (e), thereby identifying
a modulator of angiogenesis.
[0313] Transgenic animals are characterized as described above and,
based on such characteriztions, a variety of genotypes may be
usefully employed in the methods of the invention. For example, the
transgenic animal may be either homozygous or heterozygous and the
mutant allele may result in no expression (i.e., a null mutation)
or altered activity levels. A preferred transgenic animal is a
mouse, although any non-human vertebrate organism may be used,
including other mammals (e.g., rat, rabbit, sheep, cow, pig, and
horse, among others) or birds (e.g., chicken). A preferred
transgene is an insertional inactivation, or knock-out, of a gene
encoding a CCN protein (e.g., cyr61); also preferred is an
insertional inactivation resulting from the introduction, or
"knocking in", of an identifiable marker gene such as lacZ encoding
.beta.-galactosidase. Of course, many transgene constructions are
possible, including transgenes resulting from the replacement of
wild-type sequence by related sequences that specify variant amino
acid sequences. It should be understood from the preceding
discussion that the invention comprehends gene therapy approaches
involving the introduction of a transgene into a cell to treat any
of a variety of conditions or disorders, such as diseases.
[0314] Also apparent from the preceding description is another
aspect of the invention, which is drawn to a mammalian cell
comprising a cyr61 mutation selected from the group consisting of
an insertional inactivation of a cyr61 allele and a deletion of a
portion of a cyr61 allele. The mammalian cell is preferably a human
cell and the mutation is either heterozygous or homozygous. The
mutation, resulting from insertional inactivation or deletion, is
either in the coding region or a flanking region essential for
expression such as a 5' promoter region. Cells are also found
associated with non-human animals.
EXAMPLE 32
Adhesion to Platelets and Macrophages
[0315] Platelet immobilization plays an important role in wound
healing, for example by contributing to thrombosis in the process
of stanching the flow of blood. Proteins of the CCN family, such as
Cyr61 and Fisp12/CTGF, promote platelet adhesion by interacting
with the .alpha..sub.llb.beta..s- ub.3 integrin.
[0316] Recombinant Cyr61 and Fisp12/mCTGF, synthesized in a
Baculovirus expression system using Sf9 insect cells, were purified
from serum-free conditioned media by chromatography on Sepharose S
as described (Kireeva et al., [1997]; Kireeva, et al., [1996]).
SDS-PAGE analysis of purified Cyr61 and Fisp12/mCTGF revealed the
presence of single Coomassie Blue-stained bands of 40kDa and
38-kDa, respectively. On immunoblots, the purified proteins reacted
specifically with their cognate antibodies. Protein concentrations
were determined using the BCA protein assay (Pierce) with bovine
serum albumin (BSA) as the standard.
[0317] Microtiter wells were coated with purified recombinant
Fisp12/mCTGF or Cyr61, and the adhesion of isolated platelets to
these proteins was detected with .sup.125I-mAb15, an
anti-.beta..sub.3 monoclonal antibody (Frelinger et al., J. Biol.
Chem 265:6346-6352 [1990]). Platelets were obtained from venous
blood drawn from healthy donors and collected into
acid-citrate-dextrose (ACD). Washed platelets were prepared by
diffenential centrifugation as described (Kinlough-Rathbone et al.
Thromb. Haemostas 2:291-308 [1997]), and finally resuspended in
HEPES-Tyrode's buffer (5 mM HEPES, pH 7.35, 1 mM MgCl.sub.2, 1 mM
CaCl.sub.2, 135 mM NaCl, 2.7 mM KCl, 11.9 mM NaHCO.sub.3, 1 mg/ml
dextrose and 3.5 mg/ml BSA). The platelet concentration was
adjusted to 3.times.10.sup.3 platelets/ml.
[0318] Microtiter wells (Immulon 2 removawell strips, Dynex
Technologies, Inc.) were coated with Cyr61, Fisp12/mCTGF, or
fibrinogen (25 .mu.g/ml, 50 .mu.l/well) incubated overnight at
22.degree. C., and then blocked with 3% BSA at 37.degree. C. for 2
hours. Washed platelets were added to the wells (100 .mu.l/well) in
the presence and absence of platelet agonists and incubated at
37.degree. C. for 30 minutes. The wells were washed with
HEPES-Tyrode's buffer and adherent platelets were detected with
.sup.125I-mAb15, an anti-.beta..sub.3 monoclonal antibody. Exposure
to the labeled antibody (50 mM, 50 .mu.l/well) proceeded for 1 hour
at 22.degree. C. After extensive washing with HEPES-Tyrode's
buffer, bound radioactivity was determined by .gamma.-counting. In
inhibition studies, washed platelets were pre-incubated with
blocking peptides or antibodies at 37.degree. C. for 15 minutes
prior to addition to microtiter wells. In experiments to examine
the effect of divalent cation chelation, EDTA (5 mM) was added to
suspensions of washed platelets and pre-incubated at 37.degree. C.
for 15 minutes.
[0319] The anti-.beta..sub.3 antibody was radioiodinated with
carrier-free Na.sup.125I (Amersham Corp.) using the IODO-BEADS
iodination reagent (Pierce) to a specific activity of approximately
2 .mu.Ci/.mu.g. This antibody binds equally to
.alpha..sub.llb.beta..sub.3 present on activated (see below) and
unactivated platelets. As controls, BSA- and fibrinogen-coated
(KabiVitrum Inc.) wells were also used. Initially, the adhesion of
unactivated versus activated platelets to immobilized Fisp12/mCTGF
and Cyr61 was compared. To ensure that plateltes were not activated
during the washing procedures, PGl.sub.2 (100 nM), which inhibits
activation by raising platelet cAMP levels, was added to the
platelet suspensions.
[0320] Unactivated platelets failed to adhere to either protein.
However, activation of platelets with 0.1 U/ml thrombin, 500 mM
U46619, or 10 .mu.M ADP caused a dramatic increase in platelte
adhesion to both Fisp12/mCTGF- and Cyr61-coated wells. To confirm
that the adhesion process was activation-dependent, PGl.sub.2 (100
nM) was added with the agonists to prevent platelet activation.
Under these conditions, platelet adhesion to both Fisp12/mCTGF and
Cyr61 was significantly inhibited.
[0321] For comparison, platelet adhesion to fibrinogen-coated wells
was assessed. While unactivated platelets were capable of adhering
to immobilized fibrinogen at a low level, platelet adhesion to
Cyr61 and Fisp12/mCTGF appeared to be absolutely dependent on
cellular activation. Following platelet activation with strong
agonists such as thrombin and U46619, platelet adhesion to Cyr61
and Fisp12/mCTGF was comparable to fibrinogen. The weaker agonist,
ADP, caused a lesser response. Because ADP does not induce
secretion of .alpha.-granule proteins from washed human platelets
and does not induce platelet aggregation in the absence of
exogenous fibrinogen, ADP was used to induce platelet adhesion in
subsequent experiments.
[0322] To further substantiate the activation-dependent adhesion of
platelets to these proteins, an acid phosphatase assay designed to
quantitate the relative numbers of adherent platelets was
performed. This assay measured the acid phosphatase activity of
adherent platelets. Following the adhesion and washing procedures
described above, the substrate solution (0.1 mM sodium acetate, pH
5.0, 20 mM p-nitrophenylphosphate, and 0.1% Triton X-100; 150
.mu.l/well) was added and incubated for 2 hours at 37.degree. C.
The reaction was stopped by the addition of 20 .mu.l 2N NaOH, and
absorbance at 405 nm was measured. Both the .sup.125I-mAb15 binding
assay and the acid phosphatase assay for adhesion of ADP-stimulated
platelets to fibrinogen, Fisp12/mCTGF, and Cyr61, produced similar
results. Because the amounts of bound .sup.125-mAb15 were directly
proportional to the quantity of integrin
.alpha..sub.llb.beta..sub.3 on the adherent platelets, the acid
phosphatase assay was used in subsequent studies.
[0323] The adhesion of ADP-activated platelets to Fisp12/mCTGF and
Cyr61 was dose-dependent and saturable. In the presence of
PGl.sub.2, unactivated platelets adhered poorly to both proteins,
even at high coating concentrations. The specificity of the
adhesion process was characterized in inhibition studies using
anti-peptide polyclonal antibodies raised against the central
variable regions of Fisp12/mCTGF and Cyr61. On immunoblots, rabbit
polyclonal anti-Fisp12/mCTGF and anti-Cyr61, prepared as described
in Example 29, reacted specifically with Fisp12/mCTGF and Cyr61,
respectively. No cross-reactivity was observed. In addition,
anti-Fisp12/mCTGF antibody inhibited platelet adhesion to
Fisp12/mCTGF, but not to Cyr61, and anti-Cyr61 antibody inhibited
Cyr61-mediated platelet adhesion but not that mediated by
Fisp12/mCTGF. No inhibition was observed with normal rabbit IgG.
Also, neither anti-Fisp12/mCTGF antibody nor anti-Cyr61 antibody
inhibited platelet adhesion to fibrinogen-coated wells. Thus, the
abilities of Fisp12/mCTGF and Cyr61 to mediate platelet adhesion
are intrinsic properties of these proteins.
[0324] Upon platelet activation, the ligand binding affinities of
integrins .alpha..sub.llb.beta..sub.3 and .alpha..sub.V.beta..sub.3
are upregulated (Shattil, et al., Blood 91:2645-2657 [1998];
Bennett, et al., J. Biol Chem. 272:8137-8140 [1997]). To determine
whether these integrin receptors mediated platelet adhesion to
Fisp12/mCTGF and Cyr61, the inhibitory potentials of peptide
antagonists and the divalent cation chelator, EDTA, were tested.
Preincubation of platelets with EDTA at 37.degree. C. completely
abolished platelet adhesion to both proteins, indicating that the
adhesion process was divalent cation dependent. Cation dependency
of adhesion is consistent with the involvement of an integrin
receptor.
[0325] The major platelet integrin, .alpha..sub.llb.beta..sub.3, is
sensitive to inhibition by RGD-containing peptides and the
dodecapeptide H.sub.12 (H.sub.2N--HHLGGAKQAGDV--CO.sub.2H, SEQ ID
NO:29, Research Genetics Inc.) derived from the fibrinogen .gamma.
chain (Plow et al., Proc. Natl. Acad. Sci. (USA) 82:8057-8061
[1985]; Lam, et al., J. Biol Chem. 262:947-950 [1987]). The
adhesion of ADP-activated platelets to Cyr61 and Fisp12/mCTGF was
specifically inhibited by GRGDSP (SEQ ID NO:31), but not by GRGESP
(SEQ ID NO:32). (Peninsula Laboratories). Likewise, the
RGD-containing snake venom peptide echistatin (Can et al., J. Biol
Chem. 263:19827-19832 [1988], Sigma Chemical Co.) also completely
blocked platelet adhesion to both proteins. It has also been shown
that the dodecapeptide H.sub.12 preferentially interacts with
integrin .alpha..sub.llb.beta..sub.3 as compared to integrin
.alpha..sub.V.beta..sub.3 (Cheresh et al., Cell 58:945-953 [1989];
Lam et al., J. Biol. Chem. 264:3742-3749 [1989]). Thus, the finding
that H.sub.12 inhibited platelet adhesion to Cyr61 and Fisp12/mCTGF
indicated that this process was mediated by
.alpha..sub.llb.beta..sub.3 rather than .alpha..sub.V.beta..sub.3.
While the complex-specific monoclonal antibody AP-2
(anti-.alpha..sub.llb.beta..sub.3, Pidard et al., J. Biol. Chem.
258:12582-12587 [1983]) completely blocked the adhesion of
ADP-activated platelets to Fisp12/mCTGF and Cyr61, no inhibition
was observed with LM609 (anti-.alpha..sub.V.beta..sub.3; Cheresh et
al., J. Biol. Chem. 262:17703-17711 [1987]) or with normal mouse
IgG. In control samples, the adhesion of ADP-activated platelets to
fibrinogen was also completely inhibited by EDTA, RGDS, echistatin,
H.sub.12 or AP-2, but not by RGES or LM609. These results indicate
that platelet adhesion to these proteins is mediated through
interaction with activated integrin
.alpha..sub.llb.beta..sub.3.
[0326] A solid-phase binding assay to detect the receptor-ligand
interactions showed that .alpha..sub.llb.beta..sub.3 binds directly
to Fisp12/mCTGF and Cyr61. In these experiments, activated and
unactivated .alpha..sub.llb.beta..sub.3 were purified from platelet
lysates. Activated .alpha..sub.llb.beta..sub.3 was purified by RGD
affinity chromatography, as described (Knezevic et al., J. Biol.
Chem. 271:16416-16421 [1996]). Briefly, outdated human platelets
were isolated by differential centrifugation and solubilized in
lysis buffer (10 mM HEPES, pH 7.4, 0.15 M NaCl, containing 1 mM
CaCl.sub.2, 1 mM MgCl.sub.2 100 .mu.M leupeptin, 1 mM
phenylmethylsulfonyl fluoride, 10 mM-ethylmaleimide, and 50 mM
octylglucoside). The octylglucoside extract was incubated with 1 ml
GRGDSPK-coupled Sepharose 4B overnight at 4.degree. C. After
washing with 15 ml column buffer (same as lysis buffer except it
contained 25 mM octylglucoside), bound .alpha..sub.llb.beta..su-
b.3 was eluted with 1.7 mM H.sub.12 (2 ml) in column buffer. The
H.sub.12 eluate was applied to a Sephacryl S-300 High Resolution
column (1.5.times.95 cm), and .alpha..sub.llb.beta..sub.3 was
eluted with 10 mM HEPES, pH 7.4, 0.15 M NaCl, 1 mM CaCl.sub.2, 1 mM
MgCl.sub.2 and 25 mM octylglucoside.
[0327] Unactivated .alpha..sub.llb.beta..sub.3 was isolated by the
method of Fitzgerald et al., Anal. Biochem. 151:169-177 (1985),
with slight modifications. The flow-through fraction of the
GRGDSPK-Sepharose column was applied to a concanavalin A-Sepharose
4B column (1.times.20 cm). Unbound proteins were washed with 50 ml
column buffer, and bound .alpha..sub.llb.beta..sub.3 was then
eluted with 100 mM mannose dissolved in column buffer. Fractions
containing .alpha..sub.llb.beta..sub.3 were further purified on a
Sephacryl S-300 High Resolution column
[0328] To perform the solid-phase binding assay, purified
.alpha..sub.llb.beta..sub.3 was added to wells coated with either
Cyr61 or Fisp12 (mCTGF) in the presence or absence of inhibitors
and binding was allowed to proceed for 3 hours at 37.degree. C.
Unbound receptor was removed and the wells wee washed twice with
HEPES-Tyrode's Buffer. The binding of purified
.alpha..sub.llb.beta..sub.3 to Cyr61 or Fisp12/mCTGF immobilized
onto microtiter wells was detected with .sup.125I-mAb15.
[0329] Both activated and unactivated .alpha..sub.llb.beta..sub.3
were indistinguishable on SDS-PAGE analysis as detected by silver
staining. However, activated .alpha..sub.llb.beta..sub.3, but not
the unactivated receptor, was capable of binding to immobilized
fibrinogen. Likewise, greater binding of activated versus
unactivated .alpha..sub.llb.beta..sub- .3 to Fisp12/mCTGF and Cyr61
was observed. In contrast, the background bindings of activated and
unactivated .alpha..sub.llb.beta..sub.3 to control wells coated
with BSA were similar. Thus, activated, but not unactivated,
platelets adhered to Cyr61 and Fisp12/mCTGF.
[0330] To further characterize the interaction of
.alpha..sub.llb.beta..su- b.3 with Fisp12/mCTGF and Cyr61, binding
isotherms were determined for varying concentrations of
RGD-affinity purified .alpha..sub.llb.beta..sub- .3. These binding
isotherms showed that the dose-dependent binding of activated
.alpha..sub.llb.beta..sub.3 to Fisp12mCTGF and Cyr61 was saturable
with half-saturation occurring at 15 nM and 25 nM
.alpha..sub.llb.beta..sub.3, respectively. Again, no significant
binding of .alpha..sub.llb.beta..sub.3 to control BSA-coated wells
was observed. To demonstrate the specificity of the interaction,
inhibition studies were performed. As expected, the binding of
activated .alpha..sub.llb.beta..sub.3 to Fisp12/mCTGF and Cyr61 was
specifically blocked by RGDS but not by RGES. Furthermore,
echistatin and the H.sub.12 peptide also effectively inhibited
.alpha..sub.llb.beta..sub.3 binding to these proteins. These
findings are consistent with results obtained in the platelet
adhesion assay. Collectively, these functional and biochemical data
demonstrate that activated integrin .alpha..sub.llb.beta..sub.3 is
the receptor mediating activation-dependent platelet adhesion to
Cyr61 and Fisp12/mCTGF.
[0331] Thus, another aspect of the invention is a method of
screening for modulators of wound healing comprising the steps of:
(a) contacting a first activated platelet with a polypeptide of the
CCN family, such as Cyr61, and a suspected modulator; (b) further
contacting a second activated platelet with the polypeptide of step
(a); (c) measuring the binding of the first activated platelet to
the polypeptide; (d) measuring the binding of the second activated
platelet to the polypeptide; and (e) comparing the binding
measurements of steps (d) and (e), thereby identifying a modulator
of wound healing. Preferably, the wound healing involves the
participation of platelet binding in the process of blood clotting.
Also preferred are platelets presenting the
.alpha..sub.llb.beta..sub.3 integrin.
[0332] In addition to the above-described binding properties of
members of the CCN family of proteins, antibody inhibition studies
with anti-.alpha..sub.M and anti-.beta..sub.3 antibodies have shown
that Cyr61 binds to macrophages via yet another integrin, the
.alpha..sub.M.beta..sub.2 integrin. Based on these results, it is
expected that mammalian CCN proteins, such as human or mouse Cyr61,
will bind to the macrophages of mammals. It is also expected that
Cyr61 will promote the migration of macrophages, thus serving a
role in attracting and retaining macrophages at the site of a
wound. Consequently, Cyr61 is expected to play a role in the
inflammatory response of mammals, and modulation of Cyr61 activity
is expected to influence the inflammatory response.
[0333] Yet another aspect of the invention is a method of screening
for modulators of macrophage adhesion comprising the steps of: (a)
contacting a first macrophage with a polypeptide of the CCN family,
such as Cyr61, and a suspected modulator; (b) further contacting a
second macrophage with the polypeptide of step (a); (c) measuring
the binding of the first macrophage to the polypeptide; (d)
measuring the binding of the second macrophage to the polypeptide;
and (e) comparing the binding measurements of steps (d) and (e),
thereby identifying a modulator of macrophage adhesion.
EXAMPLE 33
Peptide Modulators of ECM Signaling Molecule Activity
[0334] Screening assays for modulators of cell adhesion are
designed to identify modulators (e.g., inhibitors or activators) of
ECM signaling molecule activities, such as Cyr61 activities,
involved in angiogenesis, chondrogenesis, oncogenesis, cell
adhesion, cell migration or cell proliferation. In developing a
screening assay for mudulators of cell adhesion, candidate peptide
modulators were designed as described in Example 12. In particular,
Cyr61 peptide fragments were designed with the expectation that
such peptides would modulate Cyr61 binding to an integrin receptor
such as the .alpha..sub.6.beta..sub.1 integrin.
[0335] To facilitate success with the approach to peptide design
described in Example 12, experiments were conducted to refine the
location of domains involved in one or more of the activities of
Cyr61, such as angiogenic activities. Initially, a deletion of
mouse cyr61 that removed domain IV of the encoded Cyr61
(corresponding to amino acids 282-381 of SEQ ID NO:4) was
generated. For a general description of Cyr61 domains 1-4, see Lau
et al., Exp. Cell Research 248:44-57 (1999), incorporated herein by
reference in its entirety. The deletion construct, cloned using a
conventional Baculovirus system, was expressed and was subjected to
a rat corneal implant assay as generally described in Example 19,
and the results indicated that the truncated polypeptide induced
angiogenesis. Further, the truncated polypeptide was subjected to
an in vitro endothelial cell migration assay as described in
Example 15, and the polypeptide containing Cyr61 domains I, II and
III induced cell migration.
[0336] To further localize domains involved in angiogenesis,
including endothelial cell migration, the coding regions for
domains I, II and III of Cyr61 were separately fused to a coding
sequence for glutathione S-transferase (GST), again using
conventional technology. The individual fusion constructs were
introduced into bacterial hosts, expressed, and purified with
glutathione columns, using conventional techniques. Cell adhesion
assays using endothelial cells and fibroblasts showed that, in
isolation, only domain III (corresponding to amino acids 212-218 of
SEQ ID NO:4) supported cell adhesion, and the fusion polypeptide
containing this domain, when immobilized, supported the adhesion of
both resting endothelial cells and fibroblasts.
[0337] To localize the relevant domain still further, several
overlapping peptides were synthesized. The peptides, each having a
sequence set forth in one of SEQ ID NOS:33-38, show significant
similarity to an ECM signaling molecule such as mouse Cyr61 (SEQ ID
NO:2) or human Cyr61 (SEQ ID NO:4). These peptides were then
separately tested for their capacities to inhibit Cyr61 adhesion to
endothelial cells or fibroblasts. Peptides were separately added at
various concentrations to Cyr61-coated wells containing endothelial
cells or fibroblasts, as described above. The peptide designated
TSP1 (SEQ ID NO:33) inhibited Cyr61 adhesion to endothelial cells
or fibroblasts at concentrations of 25 .mu.M or higher. None of the
other peptides tested (SEQ ID NO:34-38) showed any inhibition of
cell adhesion to Cyr61.
[0338] To determine if TSP1 was selectively inhibiting Cyr61
binding to .alpha..sub.5.beta..sub.3 or .alpha..sub.6.beta..sub.1,
two integrins found on endothelial cells that bind Cyr61, specific
monoclonal antibody blocking studies were performed. These studies
involved the separate addition of monoclonal antibody GoH3
(.alpha..sub.6-specific, including .alpha..sub.6.beta..sub.1; see
Example 29) or LM609 (.alpha..sub.5.beta..sub.3 specific; see
Example 29) to cells prior to addition of the mixture to
Cyr61-coated wells in the presence or absence of the peptide under
study. The results showed that TSP1 inhibitied Cyr61 binding to the
.alpha..sub.6.beta..sub.1 integrin, a major Cyr61 receptor active
in resting, or unactivated, endothelial cells and in fibroblasts.
TSP1 did not inhibit Cyr61 binding to .alpha..sub.V.beta..sub.3, a
major Cyr61 receptor in activated endothelial cells.
[0339] Endothelial cells interacting with Cyr61 require integrin
.alpha..sub.V.beta..sub.3 for cell migration and cell survival.
However, to form tubules in vitro in a matrigel, integrin
.alpha..sub.6.beta..sub.- 1 is required. Thus, the ability of TSP1
to inhibit tubule formation in vitro using a matrigel assay as
described in Example 15 (and as known in the art, Davis et al.,
Exp. Cell Research 216:113-123 (1995), incorporated herein by
reference in its entirety) was performed. As expected, TSP1
inhibited tubule formation in the matrigel assay.
[0340] To confirm that the TSP1 peptide was inhibiting Cyr61
activity by directly interacting with the
.alpha..sub.6.beta..sub.1, integrin, TSP1 and the peptides
collectively having SEQ ID NOS:34-38 were used in the
aforementioned cell adhesion assay in the absence of immobilized
Cyr61. In these assays, wells were coated with one of the peptides
and the immobilized peptides were then separately exposed to either
endothelial cells (resting or activated) or fibroblasts. The
results showed that TSP1, by itself, supported adhesion of
endothelial cells and fibroblasts. None of the other tested
peptides (having SEQ ID NOS:34-38, collectively) supported cell
adhesion in these assays. However, it is expected that peptides
comprising sequences from domain II (von Willebrand Factor domain)
of Cyr61 will inhibit the interaction between Cyr61 and the
.alpha..sub.V.beta..sub.3 integrin receptor, thereby inhibiting the
participation of endothelial cells in the process of angiogenesis.
Such peptides are expected to show at least 95%, and preferably
98%, similarity to a subsequence of the sequence set forth from
amino acid 93 to amino acid 211 of SEQ ID NO:4 using the comparison
algorithm of Altschul et al. used for BLAST searching in the
GenBank nucleotide database (http://www.ncbi.nim.nih.gov/) with
default settings in place. Peptides exhibiting activity are
expected to be at least seven amino acids in length, with no upper
bound, although the most economical peptides will probably have no
more than 20 amino acids.
[0341] This example establishes that peptide modulators of ECM
signaling molecules, such as mouse and human Cyr61 can be
identified using the in vitro angiogenesis and in vitro cell
adhesion assays of the invention. The modulators themselves,
showing promise as potential therapeutics for diseases and
conditions related to angiogenesis, chondrogenesis, and cell
adhesion, and for oncogenesis, cell migration and cell
proliferation, constitute another aspect of the invention.
[0342] One of ordinary skill in the art, apprised of the
information disclosed in this application, could readily identify
other peptides having Cyr61 modulating activity by designing
candidate peptides having sequence similarity to an ECM signaling
molecule such as Cyr61. Sequence variation is guided by a knowledge
of conservative amino acids substituting as described above,
peptide length may be varied between about 8-50 amino acid
residues. Further, peptide derivatives (e.g., glycosylated,
PEGylated, phosphorylated, may be used, as would be known in the
art.
[0343] Numerous modifications and variations in the practice of the
invention as illustrated in the above examples are expected to
occur to those of ordinary skill in the art. Consequently, the
illustrative examples are not intended to limit the scope of the
invention as set out in the appended claims.
Sequence CWU 1
1
38 1 1480 DNA Mus musculus CDS (180)..(1316) Mouse cyr61 cDNA
coding sequence 1 cgagagcgcc ccagagaagc gcctgcaatc tctgcgcctc
ctccgccagc acctcgagag 60 aaggacaccc gccgcctcgg ccctcgcctc
accgcactcc gggcgcattt gatcccgctg 120 ctcgccggct tgttggttct
gtgtcgccgc gctcgccccg gttcctcctg cgcgccaca 179 yatg agc tcc agc acc
ttc agg acg ctc gct gtc gcc gtc acc ctt ctc 227 Met Ser Ser Ser Thr
Phe Arg Thr Leu Ala Val Ala Val Thr Leu Leu 1 5 10 15 ycac ttg acc
aga ctg gcg ctc tcc acc tgc ccc gcc gcc tgc cac tgc 275 His Leu Thr
Arg Leu Ala Leu Ser Thr Cys Pro Ala Ala Cys His Cys 20 25 30 ycct
ctg gag gca ccc aag tgc gcc ccg gga gtc ggg ttg gtc cgg gac 323 Pro
Leu Glu Ala Pro Lys Cys Ala Pro Gly Val Gly Leu Val Arg Asp 35 40
45 yggc tgc ggc tgc tgt aag gtc tgc gct aaa caa ctc aac gag gac tgc
371 Gly Cys Gly Cys Cys Lys Val Cys Ala Lys Gln Leu Asn Glu Asp Cys
50 55 60 yagc aaa act cag ccc tgc gac cac acc aag ggg ttg gaa tgc
aat ttc 419 Ser Lys Thr Gln Pro Cys Asp His Thr Lys Gly Leu Glu Cys
Asn Phe 65 70 75 80 yggc gcc agc tcc acc gct ctg aaa ggg atc tgc
aga gct cag tca gaa 467 Gly Ala Ser Ser Thr Ala Leu Lys Gly Ile Cys
Arg Ala Gln Ser Glu 85 90 95 yggc aga ccc tgt gaa tat aac tcc aga
atc tac caa aac ggg gaa agc 515 Gly Arg Pro Cys Glu Tyr Asn Ser Arg
Ile Tyr Gln Asn Gly Glu Ser 100 105 110 yttc cag ccc aac tgt aaa
cac cag tgc aca tgt att gat ggc gcc gtg 563 Phe Gln Pro Asn Cys Lys
His Gln Cys Thr Cys Ile Asp Gly Ala Val 115 120 125 yggc tgc att
cct ctg tgt ccc caa gaa ctg tct ctc ccc aat ctg ggc 611 Gly Cys Ile
Pro Leu Cys Pro Gln Glu Leu Ser Leu Pro Asn Leu Gly 130 135 140
ytgt ccc aac ccc cgg ctg gtg aaa gtc agc ggg cag tgc tgt gaa gag
659 Cys Pro Asn Pro Arg Leu Val Lys Val Ser Gly Gln Cys Cys Glu Glu
145 150 155 160 ytgg gtt tgt gat gaa gac agc att aag gac tcc ctg
gac gac cag gat 707 Trp Val Cys Asp Glu Asp Ser Ile Lys Asp Ser Leu
Asp Asp Gln Asp 165 170 175 ygac ctc ctc gga ctc gat gcc tcg gag
gtg gag tta acg aga aac aat 755 Asp Leu Leu Gly Leu Asp Ala Ser Glu
Val Glu Leu Thr Arg Asn Asn 180 185 190 ygag tta atc gca att gga
aaa ggc agc tca ctg aag agg ctt cct gtc 803 Glu Leu Ile Ala Ile Gly
Lys Gly Ser Ser Leu Lys Arg Leu Pro Val 195 200 205 yttt ggc acc
gaa ccg cga gtt ctt ttc aac cct ctg cac gcc cat ggc 851 Phe Gly Thr
Glu Pro Arg Val Leu Phe Asn Pro Leu His Ala His Gly 210 215 220
ycag aaa tgc atc gtt cag acc acg tct tgg tcc cag tgc tcc aag agc
899 Gln Lys Cys Ile Val Gln Thr Thr Ser Trp Ser Gln Cys Ser Lys Ser
225 230 235 240 ytgc gga act ggc atc tcc aca cga gtt acc aat gac
aac cca gag tgc 947 Cys Gly Thr Gly Ile Ser Thr Arg Val Thr Asn Asp
Asn Pro Glu Cys 245 250 255 ycgc ctg gtg aaa gag acc cgg atc tgt
gaa gtg cgt cct tgt gga caa 995 Arg Leu Val Lys Glu Thr Arg Ile Cys
Glu Val Arg Pro Cys Gly Gln 260 265 270 cca gtg tac agc agc cta aaa
aag ggc aag aaa tgc agc aag acc aag 1043 Pro Val Tyr Ser Ser Leu
Lys Lys Gly Lys Lys Cys Ser Lys Thr Lys 275 280 285 aaa tcc cca gaa
cca gtc aga ttt act tat gca gga tgc tcc agt gtc 1091 Lys Ser Pro
Glu Pro Val Arg Phe Thr Tyr Ala Gly Cys Ser Ser Val 290 295 300 aag
aaa tac cgg ccc aaa tac tgc ggc tcc tgc gta gat ggc cgg tgc 1139
Lys Lys Tyr Arg Pro Lys Tyr Cys Gly Ser Cys Val Asp Gly Arg Cys 305
310 315 320 tgc aca cct ctg cag acc aga act gtg aag atg cgg ttc cga
tgc gaa 1187 Cys Thr Pro Leu Gln Thr Arg Thr Val Lys Met Arg Phe
Arg Cys Glu 325 330 335 gat gga gag atg ttt tcc aag aat gtc atg atg
atc cag tcc tgc aaa 1235 Asp Gly Glu Met Phe Ser Lys Asn Val Met
Met Ile Gln Ser Cys Lys 340 345 350 tgt aac tac aac tgc ccg cat ccc
aac gag gca tcg ttc cga ctg tac 1283 Cys Asn Tyr Asn Cys Pro His
Pro Asn Glu Ala Ser Phe Arg Leu Tyr 355 360 365 agc cta ttc aat gac
atc cac aag ttc agg gac taagtgcctc cagggttcct 1336 Ser Leu Phe Asn
Asp Ile His Lys Phe Arg Asp 370 375 agtgtgggct ggacagagga
gaagcgcaag catcatggag acgtgggtgg gcggaggatg 1396 aatggtgcct
tgctcattct tgagtagcat tagggtattt caaaactgcc aaggggctga 1456
tgtggacgga cagcagcgca gccg 1480 2 379 PRT Mus musculus 2 Met Ser
Ser Ser Thr Phe Arg Thr Leu Ala Val Ala Val Thr Leu Leu 1 5 10 15
His Leu Thr Arg Leu Ala Leu Ser Thr Cys Pro Ala Ala Cys His Cys 20
25 30 Pro Leu Glu Ala Pro Lys Cys Ala Pro Gly Val Gly Leu Val Arg
Asp 35 40 45 Gly Cys Gly Cys Cys Lys Val Cys Ala Lys Gln Leu Asn
Glu Asp Cys 50 55 60 Ser Lys Thr Gln Pro Cys Asp His Thr Lys Gly
Leu Glu Cys Asn Phe 65 70 75 80 Gly Ala Ser Ser Thr Ala Leu Lys Gly
Ile Cys Arg Ala Gln Ser Glu 85 90 95 Gly Arg Pro Cys Glu Tyr Asn
Ser Arg Ile Tyr Gln Asn Gly Glu Ser 100 105 110 Phe Gln Pro Asn Cys
Lys His Gln Cys Thr Cys Ile Asp Gly Ala Val 115 120 125 Gly Cys Ile
Pro Leu Cys Pro Gln Glu Leu Ser Leu Pro Asn Leu Gly 130 135 140 Cys
Pro Asn Pro Arg Leu Val Lys Val Ser Gly Gln Cys Cys Glu Glu 145 150
155 160 Trp Val Cys Asp Glu Asp Ser Ile Lys Asp Ser Leu Asp Asp Gln
Asp 165 170 175 Asp Leu Leu Gly Leu Asp Ala Ser Glu Val Glu Leu Thr
Arg Asn Asn 180 185 190 Glu Leu Ile Ala Ile Gly Lys Gly Ser Ser Leu
Lys Arg Leu Pro Val 195 200 205 Phe Gly Thr Glu Pro Arg Val Leu Phe
Asn Pro Leu His Ala His Gly 210 215 220 Gln Lys Cys Ile Val Gln Thr
Thr Ser Trp Ser Gln Cys Ser Lys Ser 225 230 235 240 Cys Gly Thr Gly
Ile Ser Thr Arg Val Thr Asn Asp Asn Pro Glu Cys 245 250 255 Arg Leu
Val Lys Glu Thr Arg Ile Cys Glu Val Arg Pro Cys Gly Gln 260 265 270
Pro Val Tyr Ser Ser Leu Lys Lys Gly Lys Lys Cys Ser Lys Thr Lys 275
280 285 Lys Ser Pro Glu Pro Val Arg Phe Thr Tyr Ala Gly Cys Ser Ser
Val 290 295 300 Lys Lys Tyr Arg Pro Lys Tyr Cys Gly Ser Cys Val Asp
Gly Arg Cys 305 310 315 320 Cys Thr Pro Leu Gln Thr Arg Thr Val Lys
Met Arg Phe Arg Cys Glu 325 330 335 Asp Gly Glu Met Phe Ser Lys Asn
Val Met Met Ile Gln Ser Cys Lys 340 345 350 Cys Asn Tyr Asn Cys Pro
His Pro Asn Glu Ala Ser Phe Arg Leu Tyr 355 360 365 Ser Leu Phe Asn
Asp Ile His Lys Phe Arg Asp 370 375 3 1418 DNA Homo sapiens CDS
(124)..(1266) Human cyr61 cDNA coding sequence 3 gggcgggccc
accgcgacac cgcgccgcca ccccgacccc gctgcgcacg gcctgtccgc 60
tgcacaccag cttgttggcg tcttcgtcgc cgcgctcgcc ccgggctact cctgcgcgcc
120 aca atg agc tcc cgc atc gcc agg gcg ctc gcc tta gtc gtc acc ctt
168 Met Ser Ser Arg Ile Ala Arg Ala Leu Ala Leu Val Val Thr Leu 1 5
10 15 ctc cac ttg acc agg ctg gcg ctc tcc acc tgc ccc gct gcc tgc
cac 216 Leu His Leu Thr Arg Leu Ala Leu Ser Thr Cys Pro Ala Ala Cys
His 20 25 30 tgc ccc ctg gag gcg ccc aag tgc gcg ccg gga gtc ggg
ctg gtc cgg 264 Cys Pro Leu Glu Ala Pro Lys Cys Ala Pro Gly Val Gly
Leu Val Arg 35 40 45 gac ggc tgc ggc tgc tgt aag gtc tgc gcc aag
cag ctc aac gag gac 312 Asp Gly Cys Gly Cys Cys Lys Val Cys Ala Lys
Gln Leu Asn Glu Asp 50 55 60 tgc agc aaa acg cag ccc tgc gac cac
acc aag ggg ctg gaa tgc aac 360 Cys Ser Lys Thr Gln Pro Cys Asp His
Thr Lys Gly Leu Glu Cys Asn 65 70 75 ttc ggc gcc agc tcc acc gct
ctg aag ggg atc tgc aga gct cag tca 408 Phe Gly Ala Ser Ser Thr Ala
Leu Lys Gly Ile Cys Arg Ala Gln Ser 80 85 90 95 gag ggc aga ccc tgt
gaa tat aac tcc aga atc tac caa aac ggg gaa 456 Glu Gly Arg Pro Cys
Glu Tyr Asn Ser Arg Ile Tyr Gln Asn Gly Glu 100 105 110 agt ttc cag
ccc aac tgt caa cat cag tgc aca tgt att gat ggc gcc 504 Ser Phe Gln
Pro Asn Cys Gln His Gln Cys Thr Cys Ile Asp Gly Ala 115 120 125 gtg
ggc tgc att cct ctg tgt ccc caa gaa cta tct ctc ccc aac ttg 552 Val
Gly Cys Ile Pro Leu Cys Pro Gln Glu Leu Ser Leu Pro Asn Leu 130 135
140 ggc tgt ccc aac cct cgg ctg gtc aaa gtt acc ggg cag tgc tgc gag
600 Gly Cys Pro Asn Pro Arg Leu Val Lys Val Thr Gly Gln Cys Cys Glu
145 150 155 gag tgg gtc tgt gac gag gat agt atc aag gac ccc atg gag
gac cag 648 Glu Trp Val Cys Asp Glu Asp Ser Ile Lys Asp Pro Met Glu
Asp Gln 160 165 170 175 gac ggc ctc ctt ggc aag gag ctg gga ttc gat
gcc tcc gag gtg gag 696 Asp Gly Leu Leu Gly Lys Glu Leu Gly Phe Asp
Ala Ser Glu Val Glu 180 185 190 ttg acg aga aac aat gaa ttg att gca
gtt gga aaa ggc aga tca ctg 744 Leu Thr Arg Asn Asn Glu Leu Ile Ala
Val Gly Lys Gly Arg Ser Leu 195 200 205 aag cgg ctc cct gtt ttt gga
atg gag cct cgc atc cta tac aac cct 792 Lys Arg Leu Pro Val Phe Gly
Met Glu Pro Arg Ile Leu Tyr Asn Pro 210 215 220 tta caa ggc cag aaa
tgt att gtt caa aca act tca tgg tcc cag tgc 840 Leu Gln Gly Gln Lys
Cys Ile Val Gln Thr Thr Ser Trp Ser Gln Cys 225 230 235 tca aag acc
tgt gga act ggt atc tcc aca cga gtt acc aat gac aac 888 Ser Lys Thr
Cys Gly Thr Gly Ile Ser Thr Arg Val Thr Asn Asp Asn 240 245 250 255
cct gag tgc cgc ctt gtg aaa gaa acc cgg att tgt gag gtg cgg cct 936
Pro Glu Cys Arg Leu Val Lys Glu Thr Arg Ile Cys Glu Val Arg Pro 260
265 270 tgt gga cag cca gtg tac agc agc ctg aaa aag ggc aag aaa tgc
agc 984 Cys Gly Gln Pro Val Tyr Ser Ser Leu Lys Lys Gly Lys Lys Cys
Ser 275 280 285 aag acc aag aaa tcc ccc gaa cca gtc agg ttt act tac
gct gga tgt 1032 Lys Thr Lys Lys Ser Pro Glu Pro Val Arg Phe Thr
Tyr Ala Gly Cys 290 295 300 ttg agt gtg aag aaa tac cgg ccc aag tac
tgc ggt tcc tgc gtg gac 1080 Leu Ser Val Lys Lys Tyr Arg Pro Lys
Tyr Cys Gly Ser Cys Val Asp 305 310 315 ggc cga tgc tgc acg ccc cag
ctg acc agg act gtg aag atg cgg ttc 1128 Gly Arg Cys Cys Thr Pro
Gln Leu Thr Arg Thr Val Lys Met Arg Phe 320 325 330 335 cgc tgc gaa
gat ggg gag aca ttt tcc aag aac gtc atg atg atc cag 1176 Arg Cys
Glu Asp Gly Glu Thr Phe Ser Lys Asn Val Met Met Ile Gln 340 345 350
tcc tgc aaa tgc aac tac aac tgc ccg cat gcc aat gaa gca gcg ttt
1224 Ser Cys Lys Cys Asn Tyr Asn Cys Pro His Ala Asn Glu Ala Ala
Phe 355 360 365 ccc ttc tac agg ctg ttc aat gac att cac aaa ttt agg
gac 1266 Pro Phe Tyr Arg Leu Phe Asn Asp Ile His Lys Phe Arg Asp
370 375 380 taaatgctac ctgggtttcc agggcacacc tagacaaaca agggagaaga
gtgtcagaat 1326 cagaatcatg gagaaaatgg gcgggggtgg tgtgggtgat
gggactcatt gtagaaagga 1386 agccttctca ttcttgagga gcattaaggt at 1418
4 381 PRT Homo sapiens 4 Met Ser Ser Arg Ile Ala Arg Ala Leu Ala
Leu Val Val Thr Leu Leu 1 5 10 15 His Leu Thr Arg Leu Ala Leu Ser
Thr Cys Pro Ala Ala Cys His Cys 20 25 30 Pro Leu Glu Ala Pro Lys
Cys Ala Pro Gly Val Gly Leu Val Arg Asp 35 40 45 Gly Cys Gly Cys
Cys Lys Val Cys Ala Lys Gln Leu Asn Glu Asp Cys 50 55 60 Ser Lys
Thr Gln Pro Cys Asp His Thr Lys Gly Leu Glu Cys Asn Phe 65 70 75 80
Gly Ala Ser Ser Thr Ala Leu Lys Gly Ile Cys Arg Ala Gln Ser Glu 85
90 95 Gly Arg Pro Cys Glu Tyr Asn Ser Arg Ile Tyr Gln Asn Gly Glu
Ser 100 105 110 Phe Gln Pro Asn Cys Gln His Gln Cys Thr Cys Ile Asp
Gly Ala Val 115 120 125 Gly Cys Ile Pro Leu Cys Pro Gln Glu Leu Ser
Leu Pro Asn Leu Gly 130 135 140 Cys Pro Asn Pro Arg Leu Val Lys Val
Thr Gly Gln Cys Cys Glu Glu 145 150 155 160 Trp Val Cys Asp Glu Asp
Ser Ile Lys Asp Pro Met Glu Asp Gln Asp 165 170 175 Gly Leu Leu Gly
Lys Glu Leu Gly Phe Asp Ala Ser Glu Val Glu Leu 180 185 190 Thr Arg
Asn Asn Glu Leu Ile Ala Val Gly Lys Gly Arg Ser Leu Lys 195 200 205
Arg Leu Pro Val Phe Gly Met Glu Pro Arg Ile Leu Tyr Asn Pro Leu 210
215 220 Gln Gly Gln Lys Cys Ile Val Gln Thr Thr Ser Trp Ser Gln Cys
Ser 225 230 235 240 Lys Thr Cys Gly Thr Gly Ile Ser Thr Arg Val Thr
Asn Asp Asn Pro 245 250 255 Glu Cys Arg Leu Val Lys Glu Thr Arg Ile
Cys Glu Val Arg Pro Cys 260 265 270 Gly Gln Pro Val Tyr Ser Ser Leu
Lys Lys Gly Lys Lys Cys Ser Lys 275 280 285 Thr Lys Lys Ser Pro Glu
Pro Val Arg Phe Thr Tyr Ala Gly Cys Leu 290 295 300 Ser Val Lys Lys
Tyr Arg Pro Lys Tyr Cys Gly Ser Cys Val Asp Gly 305 310 315 320 Arg
Cys Cys Thr Pro Gln Leu Thr Arg Thr Val Lys Met Arg Phe Arg 325 330
335 Cys Glu Asp Gly Glu Thr Phe Ser Lys Asn Val Met Met Ile Gln Ser
340 345 350 Cys Lys Cys Asn Tyr Asn Cys Pro His Ala Asn Glu Ala Ala
Phe Pro 355 360 365 Phe Tyr Arg Leu Phe Asn Asp Ile His Lys Phe Arg
Asp 370 375 380 5 2267 DNA Mus musculus Fisp12 cDNA coding sequence
5 gaattccgcc gacaacccca gacgccaccg cctggagcgt ccagacacca acctccgccc
60 ctgtccgaat ccaggctcca gccgcgcctc tcgtcgcctc tgcaccctgc
tgtgcatcct 120 cctaccgcgt cccgatc atg ctc gcc tcc gtc gca ggt ccc
atc agc ctc 170 Met Leu Ala Ser Val Ala Gly Pro Ile Ser Leu 1 5 10
gcc ttg gtg ctc ctc gcc ctc tgc acc cgg cct gct acg ggc cag gac 218
Ala Leu Val Leu Leu Ala Leu Cys Thr Arg Pro Ala Thr Gly Gln Asp 15
20 25 tgc agc gcg caa tgt cag tgc gca gcc gaa gca gcg ccg cac tgc
ccc 266 Cys Ser Ala Gln Cys Gln Cys Ala Ala Glu Ala Ala Pro His Cys
Pro 30 35 40 gcc ggc gtg agc ctg gtg ctg gac ggc tgc ggc tgc tgc
cgc gtc tgc 314 Ala Gly Val Ser Leu Val Leu Asp Gly Cys Gly Cys Cys
Arg Val Cys 45 50 55 gcc aag cag ctg gga gaa ctg tgt acg gag cgt
gac ccc tgc gac cca 362 Ala Lys Gln Leu Gly Glu Leu Cys Thr Glu Arg
Asp Pro Cys Asp Pro 60 65 70 75 cac aag ggc ctc ttc tgc gat ttc ggc
tcc ccc gcc aac cgc aag att 410 His Lys Gly Leu Phe Cys Asp Phe Gly
Ser Pro Ala Asn Arg Lys Ile 80 85 90 gga gtg tgc act gcc aaa gat
ggt gca ccc tgt gtc ttc ggt ggg tcg 458 Gly Val Cys Thr Ala Lys Asp
Gly Ala Pro Cys Val Phe Gly Gly Ser 95 100 105 gtg tac cgc agc ggt
gag tcc ttc caa agc agc tgc aaa tac caa tgc 506 Val Tyr Arg Ser Gly
Glu Ser Phe Gln Ser Ser Cys Lys Tyr Gln Cys 110 115 120 act tgc ctg
gat ggg gcc gtg ggc tgc gtg ccc cta tgc agc atg gac 554 Thr Cys Leu
Asp Gly Ala Val Gly Cys Val Pro Leu Cys Ser Met Asp 125 130 135 gtg
cgc ctg ccc agc cct gac tgc ccc ttc ccg aga agg gtc aag ctg 602 Val
Arg Leu Pro Ser Pro Asp Cys Pro Phe Pro Arg Arg Val Lys Leu 140 145
150 155 cct ggg aaa tgc tgc aag gag tgg gtg tgt gac gag ccc aag gac
cgc 650 Pro Gly Lys Cys Cys Lys Glu Trp Val Cys Asp Glu Pro Lys Asp
Arg 160 165 170 aca gca gtt ggc cct gcc cta gct gcc tac cga ctg gaa
gac aca ttt 698 Thr Ala
Val Gly Pro Ala Leu Ala Ala Tyr Arg Leu Glu Asp Thr Phe 175 180 185
ggc cca gac cca act atg atg cga gcc aac tgc ctg gtc cag acc aca 746
Gly Pro Asp Pro Thr Met Met Arg Ala Asn Cys Leu Val Gln Thr Thr 190
195 200 gag tgg agc gcc tgt tct aag acc tgt gga atg ggc atc tcc acc
cga 794 Glu Trp Ser Ala Cys Ser Lys Thr Cys Gly Met Gly Ile Ser Thr
Arg 205 210 215 gtt acc aat gac aat acc ttc tgc aga ctg gag aag cag
agc cgc ctc 842 Val Thr Asn Asp Asn Thr Phe Cys Arg Leu Glu Lys Gln
Ser Arg Leu 220 225 230 235 tgc atg gtc agg ccc tgc gaa gct gac ctg
gag gaa aac att aag aag 890 Cys Met Val Arg Pro Cys Glu Ala Asp Leu
Glu Glu Asn Ile Lys Lys 240 245 250 ggc aaa aag tgc atc cgg aca cct
aaa atc gcc aag cct gtc aag ttt 938 Gly Lys Lys Cys Ile Arg Thr Pro
Lys Ile Ala Lys Pro Val Lys Phe 255 260 265 gag ctt tct ggc tgc acc
agt gtg aag aca tac agg gct aag ttc tgc 986 Glu Leu Ser Gly Cys Thr
Ser Val Lys Thr Tyr Arg Ala Lys Phe Cys 270 275 280 ggg gtg tgc aca
gac ggc cgc tgc tgc aca ccg cac aga acc acc act 1034 Gly Val Cys
Thr Asp Gly Arg Cys Cys Thr Pro His Arg Thr Thr Thr 285 290 295 ctg
cca gtg gag ttc aaa tgc ccc gat ggc gag atc atg aaa aag aat 1082
Leu Pro Val Glu Phe Lys Cys Pro Asp Gly Glu Ile Met Lys Lys Asn 300
305 310 315 atg atg ttc atc aag acc tgt gcc tgc cat tac aac tgt cct
ggg gac 1130 Met Met Phe Ile Lys Thr Cys Ala Cys His Tyr Asn Cys
Pro Gly Asp 320 325 330 aat gac atc ttt gag tcc ctg tac tac agg aag
atg tac gga gac atg 1178 Asn Asp Ile Phe Glu Ser Leu Tyr Tyr Arg
Lys Met Tyr Gly Asp Met 335 340 345 gcg taaagccagg aagtaaggga
cacgaactca ttagactata acttgaactg 1231 Ala agttgcatct cattttcttc
tgtaaaaaca attacagtag cacattaatt taaatctgtg 1291 tttttaacta
ccgtgggagg aactatccca ccaaagtgag aacgttatgt catggccata 1351
caagtagtct gtcaacctca gacactggtt tcgagacagt ttacacttga cagttgttca
1411 ttagcgcaca gtgccagaac gcacactgag gtgagtctcc tggaacagtg
gagatgccag 1471 gagaaagaaa gacaggtact agctgaggtt attttaaaag
cagcagtgtg cctacttttt 1531 ggagtgtaac cggggaggga aattatagca
tgcttgcaga cagacctgct ctagcgagag 1591 ctgagcatgt gtcctccact
agatgaggct gagtccagct gttctttaag aacagcagtt 1651 tcagcctctg
accattctga ttccagtgac acttgtcagg agtcagagcc ttgtctgtta 1711
gactggacag cttgtggcaa gtaagtttgc ctgtaacaag ccagattttt attgatattg
1771 taaatattgt ggatatatat atatatatat atatttgtac agttatctaa
gttaatttaa 1831 agtcatttgt ttttgtttta agtgcttttg ggattttaaa
ctgatagcct caaactccaa 1891 acaccatagg taggacacga agcttatctg
tgattcaaaa caaaggagat actgcagtgg 1951 gaattgtgac ctgagtgact
ctctgtcaga acaaacaaat gctgtgcagg tgataaagct 2011 atgtattgga
agtcagattt ctagtaggaa atgtggtcaa atccctgttg gtgaacaaat 2071
ggcctttatt aagaaatggc tggctcaggg taaggtccga ttcctaccag gaagtgcttg
2131 ctgcttcttt gattatgact ggtttggggt ggggggcagt ttatttgttg
agagtgtgac 2191 caaaagttac atgtttgcac ctttctagtt gaaaataaag
tatatatata ttttttatat 2251 gaaaaaaaag gaattc 2267 6 348 PRT Mus
musculus 6 Met Leu Ala Ser Val Ala Gly Pro Ile Ser Leu Ala Leu Val
Leu Leu 1 5 10 15 Ala Leu Cys Thr Arg Pro Ala Thr Gly Gln Asp Cys
Ser Ala Gln Cys 20 25 30 Gln Cys Ala Ala Glu Ala Ala Pro His Cys
Pro Ala Gly Val Ser Leu 35 40 45 Val Leu Asp Gly Cys Gly Cys Cys
Arg Val Cys Ala Lys Gln Leu Gly 50 55 60 Glu Leu Cys Thr Glu Arg
Asp Pro Cys Asp Pro His Lys Gly Leu Phe 65 70 75 80 Cys Asp Phe Gly
Ser Pro Ala Asn Arg Lys Ile Gly Val Cys Thr Ala 85 90 95 Lys Asp
Gly Ala Pro Cys Val Phe Gly Gly Ser Val Tyr Arg Ser Gly 100 105 110
Glu Ser Phe Gln Ser Ser Cys Lys Tyr Gln Cys Thr Cys Leu Asp Gly 115
120 125 Ala Val Gly Cys Val Pro Leu Cys Ser Met Asp Val Arg Leu Pro
Ser 130 135 140 Pro Asp Cys Pro Phe Pro Arg Arg Val Lys Leu Pro Gly
Lys Cys Cys 145 150 155 160 Lys Glu Trp Val Cys Asp Glu Pro Lys Asp
Arg Thr Ala Val Gly Pro 165 170 175 Ala Leu Ala Ala Tyr Arg Leu Glu
Asp Thr Phe Gly Pro Asp Pro Thr 180 185 190 Met Met Arg Ala Asn Cys
Leu Val Gln Thr Thr Glu Trp Ser Ala Cys 195 200 205 Ser Lys Thr Cys
Gly Met Gly Ile Ser Thr Arg Val Thr Asn Asp Asn 210 215 220 Thr Phe
Cys Arg Leu Glu Lys Gln Ser Arg Leu Cys Met Val Arg Pro 225 230 235
240 Cys Glu Ala Asp Leu Glu Glu Asn Ile Lys Lys Gly Lys Lys Cys Ile
245 250 255 Arg Thr Pro Lys Ile Ala Lys Pro Val Lys Phe Glu Leu Ser
Gly Cys 260 265 270 Thr Ser Val Lys Thr Tyr Arg Ala Lys Phe Cys Gly
Val Cys Thr Asp 275 280 285 Gly Arg Cys Cys Thr Pro His Arg Thr Thr
Thr Leu Pro Val Glu Phe 290 295 300 Lys Cys Pro Asp Gly Glu Ile Met
Lys Lys Asn Met Met Phe Ile Lys 305 310 315 320 Thr Cys Ala Cys His
Tyr Asn Cys Pro Gly Asp Asn Asp Ile Phe Glu 325 330 335 Ser Leu Tyr
Tyr Arg Lys Met Tyr Gly Asp Met Ala 340 345 7 2075 DNA Homo sapiens
CTGF cDNA coding sequence 7 cccggccgac agccccgaga cgacagcccg
gcgcgtcccg gtccccacct ccgaccaccg 60 ccagcgctcc aggccccgcg
ctccccgctc gccgccaccg cgccctccgc tccgcccgca 120 gtgccaacc atg acc
gcc gcc agt atg ggc ccc gtc cgc gtc gcc ttc gtg 171 Met Thr Ala Ala
Ser Met Gly Pro Val Arg Val Ala Phe Val 1 5 10 gtc ctc ctc gcc ctc
tgc agc cgg ccg gcc gtc ggc cag aac tgc agc 219 Val Leu Leu Ala Leu
Cys Ser Arg Pro Ala Val Gly Gln Asn Cys Ser 15 20 25 30 ggg ccg tgc
cgg tgc ccg gac gag ccg gcg ccg cgc tgc ccg gcg ggc 267 Gly Pro Cys
Arg Cys Pro Asp Glu Pro Ala Pro Arg Cys Pro Ala Gly 35 40 45 gtg
agc ctc gtg ctg gac ggc tgc ggc tgc tgc cgc gtc tgc gcc aag 315 Val
Ser Leu Val Leu Asp Gly Cys Gly Cys Cys Arg Val Cys Ala Lys 50 55
60 cag ctg ggc gag ctg tgc acc gag cgc gac ccc tgc gac ccg cac aag
363 Gln Leu Gly Glu Leu Cys Thr Glu Arg Asp Pro Cys Asp Pro His Lys
65 70 75 ggc ctc ttc tgt gac ttc ggc tcc ccg gcc aac cgc aag atc
ggc gtg 411 Gly Leu Phe Cys Asp Phe Gly Ser Pro Ala Asn Arg Lys Ile
Gly Val 80 85 90 tgc acc gcc aaa gat ggt gct ccc tgc atc ttc ggt
ggt acg gtg tac 459 Cys Thr Ala Lys Asp Gly Ala Pro Cys Ile Phe Gly
Gly Thr Val Tyr 95 100 105 110 cgc agc gga gag tcc ttc cag agc agc
tgc aag tac cag tgc acg tgc 507 Arg Ser Gly Glu Ser Phe Gln Ser Ser
Cys Lys Tyr Gln Cys Thr Cys 115 120 125 ctg gac ggg gcg gtg ggc tgc
atg ccc ctg tgc agc atg gac gtt cgt 555 Leu Asp Gly Ala Val Gly Cys
Met Pro Leu Cys Ser Met Asp Val Arg 130 135 140 ctg ccc agc cct gac
tgc ccc ttc ccg agg agg gtc aag ctg ccc ggg 603 Leu Pro Ser Pro Asp
Cys Pro Phe Pro Arg Arg Val Lys Leu Pro Gly 145 150 155 aaa tgc tgc
gag gag tgg gtg tgt gac gag ccc aag gac caa acc gtg 651 Lys Cys Cys
Glu Glu Trp Val Cys Asp Glu Pro Lys Asp Gln Thr Val 160 165 170 gtt
ggg cct gcc ctc gcg gct tac cga ctg gaa gac acg ttt ggc cca 699 Val
Gly Pro Ala Leu Ala Ala Tyr Arg Leu Glu Asp Thr Phe Gly Pro 175 180
185 190 gac cca act atg att aga gcc aac tgc ctg gtc cag acc aca gag
tgg 747 Asp Pro Thr Met Ile Arg Ala Asn Cys Leu Val Gln Thr Thr Glu
Trp 195 200 205 agc gcc tgt tcc aag acc tgt ggg atg ggc atc tcc acc
cgg gtt acc 795 Ser Ala Cys Ser Lys Thr Cys Gly Met Gly Ile Ser Thr
Arg Val Thr 210 215 220 aat gac aac gcc tcc tgc agg cta gag aag cag
agc cgc ctg tgc atg 843 Asn Asp Asn Ala Ser Cys Arg Leu Glu Lys Gln
Ser Arg Leu Cys Met 225 230 235 gtc agg cct tgc gaa gct gac ctg gaa
gag aac att aag aag ggc aaa 891 Val Arg Pro Cys Glu Ala Asp Leu Glu
Glu Asn Ile Lys Lys Gly Lys 240 245 250 aag tgc atc cgt act ccc aaa
atc tcc aag cct atc aag ttt gag ctt 939 Lys Cys Ile Arg Thr Pro Lys
Ile Ser Lys Pro Ile Lys Phe Glu Leu 255 260 265 270 tct ggc tgc acc
agc atg aag aca tac cga gct aaa ttc tgt gga gta 987 Ser Gly Cys Thr
Ser Met Lys Thr Tyr Arg Ala Lys Phe Cys Gly Val 275 280 285 tgt acc
gac ggc cga tgc tgc acc ccc cac aga acc acc acc ctg ccg 1035 Cys
Thr Asp Gly Arg Cys Cys Thr Pro His Arg Thr Thr Thr Leu Pro 290 295
300 gtg gag ttc aag tgc cct gac ggc gag gtc atg aag aag aac atg atg
1083 Val Glu Phe Lys Cys Pro Asp Gly Glu Val Met Lys Lys Asn Met
Met 305 310 315 ttc atc aag acc tgt gcc tgc cat tac aac tgt ccc gga
gac aat gac 1131 Phe Ile Lys Thr Cys Ala Cys His Tyr Asn Cys Pro
Gly Asp Asn Asp 320 325 330 atc ttt gaa tcg ctg tac tac agg aag atg
tac gga gac atg gca 1176 Ile Phe Glu Ser Leu Tyr Tyr Arg Lys Met
Tyr Gly Asp Met Ala 335 340 345 tgaagccaga gagtgagaga cattaactca
ttagactgga acttgaactg attcacatct 1236 catttttccg taaaaatgat
ttcagtagca caagttattt aaatctgttt ttctaactgg 1296 gggaaaagat
tcccacccaa ttcaaaacat tgtgccatgt caaacaaata gtctatcttc 1356
cccagacact ggtttgaaga atgttaagac ttgacagtgg aactacatta gtacacagca
1416 ccagaatgta tattaaggtg tggctttagg agcagtggga gggtaccggc
ccggttagta 1476 tcatcagatc gactcttata cgagtaatat gcctgctatt
tgaagtgtaa ttgagaagga 1536 aaattttagc gtgctcactg acctgcctgt
agccccagtg acagctagga tgtgcattct 1596 ccagccatca agagactgag
tcaagttgtt ccttaagtca gaacagcaga ctcagctctg 1656 acattctgat
tcgaatgaca ctgttcagga atcggaatcc tgtcgattag actggacagc 1716
ttgtggcaag tgaatttgcc tgtaacaagc cagatttttt aaaatttata ttgtaaatat
1776 tgtgtgtgtg tgtgtgtgtg tatatatata tatatatgta cagttatcta
agttaattta 1836 aagttgtttg tgccttttta tttttgtttt taatgctttg
atatttcaat gttagcctca 1896 atttctgaac accataggta gaatgtaaag
cttgtctgat cgttcaaagc atgaaatgga 1956 tacttatatg gaaattctgc
tcagatagaa tgacagtccg tcaaaacaga ttgtttgcaa 2016 aggggaggca
tcagtgtctt ggcaggctga tttctaggta ggaaatgtgg tagctcacg 2075 8 349
PRT Homo sapiens 8 Met Thr Ala Ala Ser Met Gly Pro Val Arg Val Ala
Phe Val Val Leu 1 5 10 15 Leu Ala Leu Cys Ser Arg Pro Ala Val Gly
Gln Asn Cys Ser Gly Pro 20 25 30 Cys Arg Cys Pro Asp Glu Pro Ala
Pro Arg Cys Pro Ala Gly Val Ser 35 40 45 Leu Val Leu Asp Gly Cys
Gly Cys Cys Arg Val Cys Ala Lys Gln Leu 50 55 60 Gly Glu Leu Cys
Thr Glu Arg Asp Pro Cys Asp Pro His Lys Gly Leu 65 70 75 80 Phe Cys
Asp Phe Gly Ser Pro Ala Asn Arg Lys Ile Gly Val Cys Thr 85 90 95
Ala Lys Asp Gly Ala Pro Cys Ile Phe Gly Gly Thr Val Tyr Arg Ser 100
105 110 Gly Glu Ser Phe Gln Ser Ser Cys Lys Tyr Gln Cys Thr Cys Leu
Asp 115 120 125 Gly Ala Val Gly Cys Met Pro Leu Cys Ser Met Asp Val
Arg Leu Pro 130 135 140 Ser Pro Asp Cys Pro Phe Pro Arg Arg Val Lys
Leu Pro Gly Lys Cys 145 150 155 160 Cys Glu Glu Trp Val Cys Asp Glu
Pro Lys Asp Gln Thr Val Val Gly 165 170 175 Pro Ala Leu Ala Ala Tyr
Arg Leu Glu Asp Thr Phe Gly Pro Asp Pro 180 185 190 Thr Met Ile Arg
Ala Asn Cys Leu Val Gln Thr Thr Glu Trp Ser Ala 195 200 205 Cys Ser
Lys Thr Cys Gly Met Gly Ile Ser Thr Arg Val Thr Asn Asp 210 215 220
Asn Ala Ser Cys Arg Leu Glu Lys Gln Ser Arg Leu Cys Met Val Arg 225
230 235 240 Pro Cys Glu Ala Asp Leu Glu Glu Asn Ile Lys Lys Gly Lys
Lys Cys 245 250 255 Ile Arg Thr Pro Lys Ile Ser Lys Pro Ile Lys Phe
Glu Leu Ser Gly 260 265 270 Cys Thr Ser Met Lys Thr Tyr Arg Ala Lys
Phe Cys Gly Val Cys Thr 275 280 285 Asp Gly Arg Cys Cys Thr Pro His
Arg Thr Thr Thr Leu Pro Val Glu 290 295 300 Phe Lys Cys Pro Asp Gly
Glu Val Met Lys Lys Asn Met Met Phe Ile 305 310 315 320 Lys Thr Cys
Ala Cys His Tyr Asn Cys Pro Gly Asp Asn Asp Ile Phe 325 330 335 Glu
Ser Leu Tyr Tyr Arg Lys Met Tyr Gly Asp Met Ala 340 345 9 25 DNA
Artificial Sequence Description of Artificial Sequence primer 9
ggggatctgt gacgagccca aggac 25 10 26 DNA Artificial Sequence
Description of Artificial Sequence primer 10 gggaattcga ccaggcagtt
ggctcg 26 11 26 DNA Artificial Sequence Description of Artificial
Sequence primer 11 ggggatcctg tgatgaagac agcatt 26 12 26 DNA
Artificial Sequence Description of Artificial Sequence primer 12
gggaattcaa cgatgcattt ctggcc 26 13 21 PRT Artificial Sequence
Description of Artificial Sequence synthetic peptide 13 Asp Gly Cys
Gly Cys Cys Lys Val Cys Ala Lys Gln Leu Asn Glu Asp 1 5 10 15 Cys
Ser Lys Thr Gln 20 14 21 PRT Artificial Sequence Description of
Artificial Sequence synthetic peptide 14 Pro Asn Cys Lys His Gln
Cys Thr Cys Ile Asp Gly Ala Val Gly Cys 1 5 10 15 Ile Pro Leu Cys
Pro 20 15 24 PRT Artificial Sequence Description of Artificial
Sequence synthetic peptide 15 Cys Ile Val Gln Thr Thr Ser Trp Ser
Gln Cys Ser Lys Ser Cys Gly 1 5 10 15 Thr Gly Ile Ser Thr Arg Val
Thr 20 16 26 PRT Artificial Sequence Description of Artificial
Sequence synthetic peptide 16 Ile Ser Thr Arg Val Thr Asn Asp Asn
Pro Glu Cys Arg Leu Val Lys 1 5 10 15 Glu Thr Arg Ile Cys Glu Val
Arg Pro Cys 20 25 17 21 PRT Artificial Sequence Description of
Artificial Sequence synthetic peptide 17 Lys Tyr Cys Gly Ser Cys
Val Asp Gly Arg Cys Cys Thr Pro Leu Gln 1 5 10 15 Thr Arg Thr Val
Lys 20 18 39 DNA Artificial Sequence Description of Artificial
Sequence primer fH1 18 gcggcatgca gcgcgaccgc gaaatcccca gaaccagtc
39 19 42 DNA Artificial Sequence Description of Artificial Sequence
primer rH1 19 tcgcgctgca tgccgcgccc gcttttaggc tgctgtacac tg 42 20
32 DNA Artificial Sequence Description of Artificial Sequence
primer fH2 20 gtcgcggcat acgcgcccaa atactgcggc tc 32 21 31 DNA
Artificial Sequence Description of Artificial Sequence primer rH2
21 gcgcgtatgc cgcgacactg gagcatcctg c 31 22 18 DNA Artificial
Sequence Description of Artificial Sequence upstream PCR primer 22
cagaccacgt cttggtcc 18 23 19 DNA Artificial Sequence Description of
Artificial Sequence downstream PCR primer 23 gaataggctg tacagtcgg
19 24 20 DNA Artificial Sequence Description of Artificial Sequence
primer 24 cacaacagaa gccaggaacc 20 25 20 DNA Artificial Sequence
Description of Artificial Sequence lower PCR primer 25 gaggggacga
cgacagtatc 20 26 20 DNA Artificial Sequence Description of
Artificial Sequence upper PCR primer 26 caacggagcc aggggaggtg 20 27
20 DNA Artificial Sequence Description of Artificial Sequence lower
wild-type PCR primer 27 cggcgacaca gaaccaacaa 20 28 20 DNA
Artificial Sequence Description of Artificial Sequence lower mutant
PCR primer 28 gaggggacga cgacagtatc 20 29 12 PRT Artificial
Sequence Description of Artificial Sequence synthetic peptide 29
His His Leu Gly Gly Ala Lys Gln Ala Gly Asp Val 1 5 10 30 37 PRT
Artificial Sequence Description of Artificial Sequence synthetic
peptide 30 Ser Leu Lys Ala Gly Ala Ala Cys Ser Ala Thr Ala Lys Ser
Pro Glu 1 5
10 15 Pro Val Arg Phe Thr Tyr Ala Gly Cys Ser Ser Val Ala Ala Tyr
Ala 20 25 30 Pro Lys Tyr Cys Gly 35 31 6 PRT Artificial Sequence
Description of Artificial Sequence synthetic peptide 31 Gly Arg Gly
Asp Ser Pro 1 5 32 6 PRT Artificial Sequence Description of
Artificial Sequence synthetic peptide 32 Gly Arg Gly Glu Ser Pro 1
5 33 17 PRT Artificial Sequence Description of Artificial Sequence
TSP1 33 Gly Gln Lys Cys Ile Val Gln Thr Thr Ser Trp Ser Gln Cys Ser
Lys 1 5 10 15 Ser 34 20 PRT Artificial Sequence Description of
Artificial Sequence TSP2 34 Ser Trp Ser Gln Cys Ser Lys Ser Cys Gly
Thr Gly Ile Ser Thr Arg 1 5 10 15 Val Thr Asn Asp 20 35 20 PRT
Artificial Sequence Description of Artificial Sequence TSP3 35 Gly
Ile Ser Thr Arg Val Thr Asn Asp Asn Pro Glu Cys Arg Leu Val 1 5 10
15 Lys Glu Thr Arg 20 36 16 PRT Artificial Sequence Description of
Artificial Sequence TSP4 36 Arg Leu Val Lys Glu Thr Arg Ile Cys Glu
Val Arg Pro Cys Gly Gln 1 5 10 15 37 18 PRT Artificial Sequence
Description of Artificial Sequence H1 37 Tyr Ser Ser Leu Lys Lys
Gly Lys Lys Cys Ser Lys Thr Lys Lys Ser 1 5 10 15 Pro Glu 38 13 PRT
Artificial Sequence Description of Artificial Sequence H2 38 Ser
Ser Val Lys Lys Tyr Arg Pro Lys Tyr Cys Gly Ser 1 5 10
* * * * *
References